Sand beds in Freshwater tanks    2/16/08
Hi Bob, Amy here I have the Oscars with "HLLE" I have been writing you the last couple of days. So much information on this sight. It's really great. I haven't really seen that sand beds are that common for freshwater fish.
<Mmm, no... for a few "reasons"... mainly just perceived as being too hard to maintain>
I just yesterday cleaned all the rocks and sand in my upper aquarium 220 gal. I never told you I had a partial sand bed. I have very fine rocks and about 80 pounds of Moonlite sand total of about 4 inches deep. It seems to be enough sand to fill the gaps between my fine gravel. Maybe that's why I have those little white worms. I also see air bubbles in my rocks at times. That should be good. Maybe not now that I cleaned them, no more bubbles. My Aquarium has been set up for about 1.5 years now. I do clean my gravel bed in my upper tank, but not very often. Normally I just get the loose debris off the surface. The last couple of days, I really cleaned all my rocks because of my problem with "HLLE". Did I just remove all the good bacteria from my tank?
<Mmm, assuredly not>
The sand / gravel really wasn't that dirty, probably because it is so dense. I did not move my stationary rocks and caves to clean. They cover about half of my aquarium floor. So there should still be bacteria there. In the future how should I clean the sand / gravel in my upper tank?
<... this is posted as well... Please learn to/use the indices and search tool on WWM>
Is a sand bed beneficial to freshwater fish?
<Can be if maintained adequately>
When I set up I thought " more natural" is better, right. I know sand beds are great for saltwater and I may change over some day. I want to do the best for my fish. Thanks for all your advise. Amy
<Please read here: http://wetwebmedia.com/FWSubWebIndex/fwsetupindex.htm
the second tray, FW substrates, the linked files above...>
Oh one more thing. I am going to feed my fish food with Metronidazole in it. I also think I'm going to start treating for fin rot today, with Pro Series Fungus Cure. Let me know if you think that might be a bad idea. When the fin rot treatment is completed I was going treat my water again with Metronidazole.
<Please... read re on WWM. I would only treat once with Metronidazole...>
Just so you know, I always remove the charcoal when I treat with medications. Thanks again for the help. I'm going to try feeding peas and crickets today. I hope they like it. Thanks again, Amy
<Keep reading my young friend. BobF>

A few questions for Neale... Silica sand use in FW, Goldfish sys.   1/25/08
Hi Neale,
<Nicole,>
Hope you are doing well!
<Yep.>
I thought I would ask you, since I have heard you say before that you use silica sand (aka silver sand, aka pool filter sand) in your tanks...have you ever heard of any problems arising from goldfish being kept in an aquarium with such a substrate?
<Goldfish love sand! Your main problems are these: [1] Sand doesn't hide faeces the way gravel does. Faecal matter in tanks with gravel sinks between the grains, where you can't see it. It doesn't go away, but at least you can't see it until you stir the gravel. In a tank with sand, faeces sit on top of the sand. If you have a strong filter, they'll get sucked into the filter, but otherwise it can look messy. I find "spot cleaning" with an old turkey baster a great solution. If something looks too yucky, suck it up, and dump onto a houseplant. Problem [2] is that Goldfish can kick the sand about when they root about for food. They're happy as the proverbial pigs, but if the filter inlet is too close to the bottom of the tank, you can end up getting sand in the filter.>
My friend tried using sand but missed his undergravel filter, so he's giving me 50# of silica sand, and I was considering using that for my future 30 gallon semi-planted goldfish tank. I have read - admittedly, on forums of questionable repute - that this can be problematic, causing intestinal impactions in the goldfish due to swallowing mouthfuls of sand when they are rooting about in the gravel, and have also heard it can irritate their gills as it passes.
<Neither of these sounds likely. For a start, these fish live in muddy environments where they routinely throw all kinds of muck through their gills. But from my personal experience I've see smaller fish such as Corydoras and gobies thriving in sandy tanks, let alone massive great things like Goldies.>
Would you know if there is any truth to this? I suspect there is not, but if so, my next choice would be organic potting soil with a layer of fine gravel on top, since I have read that soil can be a fine substrate for a planted tank.
<Potting soil is rich in nitrate and phosphate, so tends to cause problems with algae. I do use pond soil in aquaria, which is formulated to be nitrate-free, but plain vanilla loams and soils tend not to be recommended. A better choice is coir (coconut fibre) which is relatively inert but looks very nice. Your problem here is that as much as the fish love this stuff, it makes the water completely cloudy *unless* you have teeny-tiny fish such as killifish that can't root about.>
I have silica sand on two of my tanks, and I notice that (for me, anyway) it does seem to encourage smudge algae, or brown algae or diatoms - whichever it may be! This is fine since both tanks have a trio of Otos, and they seem to relish the stuff, but I am nervous about keeping Otos with goldfish, so I'll just have to step up on the water changes and do two 30% changes weekly.
<The jury is out on whether silica sand genuinely creates a diatom bloom or not. Here's the issue: silica sand is basically glass, and both are effectively non-soluble. The amount of silicon coming out of silica sand will be completely negligible if the chemists are to be believed. My thinking is that silica sand is more difficult to clean than gravel, so perhaps more silt gets in, and *this* promotes algae. Perhaps also the brighter colour of silica sand makes algae more obvious. Finally, it's worth mentioning that all new tanks get diatom blooms; it seems to be part of what happens when you set aquaria up.>
My plan is to keep 2 shubunkins, and a Synodontis eupterus together in the 30 gallon tank. I know this is woefully small for the Syno, but he is still "only" 6 inches and he is moving to a 55 gallon tank by the end of the year. If the shubunkins ever get too large where maintenance becomes impossible, the same friend who is giving me the sand has a natural clay lined pond that already has a couple of full grown comets in there.
<Hmm... some Synodontis are confirmed fin-nibblers, so do your research here carefully.>
I plan on massively over filtering the tank: hang-on back, 330 gph filter rated for 60 gallons, plus a Penn Plax 115 gph canister filter rated for 30 gallons, with a spray bar, and chock full of sponges and ceramic noodles. The hang-on back filter will contain filter floss contained in 800 micron media bags. The floss I plan on rinsing weekly and replacing monthly. Does this sound all right?
<Sounds great. The more you rinse the floss, the less often you actually need to replace it, by the way.>
The plants I intend to keep are a few of the inedible kinds - Java fern, Java moss. Some regularly thinned Salvinia on the top, and Water Wisteria in the substrate. I plan on trying Elodea/Anacharis but I suspect it will be chomped on heavily.
<Elodea = goldfish food.>
Is there any benefit to adding a thin layer of Laterite (20 oz.) and pouring the sand on top? (That is, if the silica sand is acceptable, of course.)
<Laterite mixed with fine gravel, and then topped with sand (with a gravel tidy between the two layers) works very well. It's a trifle old school, but serviceable.>
I would really appreciate your comments, and any advice, since I am a planted tank newbie. I have never had luck with plants; I do realize now that lack of lighting has been the reason, along with being sold houseplants. I know better now! My water is very hard and alkaline (alkalinity is off the charts at 300 ppm on my test kit) and I am lucky enough to be on a well, so no need for dechlorinator either.
<Goldfish love this kind of water.>
The city water I had before this was dreadful, very low in alkalinity.
Fishkeeping is loads easier now, it almost felt like you were speaking to me directly when I read your hard water article! I've been meaning to try some fish that would really appreciate the hard water and plant combination, I am hoping that the goldfish will.
<You get it! Yep, everyone thinks hard water is a bad thing. It's actually a blessing in disguise, once you understand how aquaria go wrong, and what it is water hardness actually does to help.>
Thank you so much for your time. Also, your article about fish for a 10 gallon tank was superb! I suspect you had lots more to say, but had to keep it concise due to space constraints. I am definitely keeping it sandwiched in my aquarium books for future reference.
<Glad you enjoyed the article! Yes, there is a lot to say about the topic of choosing the right fish for a given aquarium.>
Take care, and thanks again!
Nicole
<Happy to help.>
P.S. By any chance, do you remember what kind of Synos these were?
http://en.wikipedia.org/wiki/Ram_cichlid
I noticed you were the author of this stunning photo! The sand looks beautiful, I've never seen such a lovely yellow color, although I am guessing it's a trick of the light and it's really silver sand...
<The sand does look very yellow under certain lights, especially if you have some bogwood in the tank tinting the water brown. Those cats are Synodontis nigriventris, a nicely-behaved small, schooling Syno ideally suited to community tanks although it is one of the fin-nibblers, so you do need to watch it carefully if mixed with slow-moving fish.>

Black (Silica) Sand grain size? 01/21/2008
Hello crew member.
<That would be me, Neale.>
I hope you're having a good morning/afternoon/evening (which ever it is in your part of the world).
<Hmm... just about lunchtime here in Blighty.>
If I have overlooked the answer to this I am sorry and please feel free to direct me to the link as I am more then happy to research/read for
myself.
<OK.>
I have read several times where it has been stated that black sand (I think specifically black silica sand) is good, not only for bringing out the colour of freshwater tropicals, but also for certain bottom dwelling fish such as Corydoras.
<Absolutely. Sand (actually mud) is what Corydoras like best. They stick their heads right into it, and spew the stuff out of their gills, trapping organic materials in the process. My Corydoras spend the summers in a small pond filled with mud, and they love it! Almost all freshwater fish live in places where the substrate is dark. But in aquaria we often use light- or brightly-coloured gravel or sand. The fish try to adapt their colours to this, and effectively mute the colours so they are less obvious to predators. The result is that we rarely see freshwater fish in their full colouration. (At least, for wild-type fish; fancy varieties of things like Goldfish are different.) Use a dark substrate and the colours on most fishes, but especially cichlids and tetras, really come alive.>
I am currently in the process of setting up a new 45G freshwater tank (when I say in the process of setting up I mean it is currently sitting on a stand in my living room, empty and bare of all things including lights, filters, heaters, substrate etc... whereupon I come home from work every day and stare at it trying to decide what I want to ultimately do with it). I have used gravel in all my previous freshwater tanks and I like the idea of trying something new. Recently black sand has peaked my interest (I think Neale might have mentioned it to someone in the past week or so in one of his answers to a question).
<Black sand is indeed the best. It can be a bit pricey, so shop around for the best deal. Also, don't forget only the surface needs to be sand. The bottom layer can be fine gravel, and you separate the two with a "gravel tidy". Surprisingly enough, the sand behaves itself and stays at the top. Mostly, anyway!>
Well it would seem that none of the aquarium shops here carry anything other then calcium carbonate sand, so as Neale suggested in his "Nice Bottoms: Choosing the right substrate for your aquarium" I went to some garden centres. I finally found one that stocks black silica sand.
<Cool!>
So here's my question (finally). What grain size is best? They carry 5mm, 3mm and 1mm grain size, and I have to say even the 1mm grain size seems pretty big to me. I had envisioned something quite a bit finer then what I have actually found. Is the 1mm grain size what I'm looking for in my quest for the illusive "black silica sand" or should I continue my search for something finer and if
so how fine (e.g. 0.5mm).
<It actually shouldn't matter much. Finer sand looks really nice, but depending on the fish you're keeping, it does have the downside of getting everywhere (e.g., inside the filter) if the fish move it about too much. Corydoras and tetras aren't a problem here, but things like Plecs and Clown Loaches would be. So if you're likely to keep robust fish, then a coarse grade of sand would be perfect. But as a default, I think the 1 mm sand is definitely worthwhile. Your catfish will thank you! You haven't lived until you've seen a Corydoras with its nose buried in the sand and it's little fins quivering with delight.>
Thank you
Amanda
<Happy to help, Neale.>

Re: Black (Silica) Sand grain size? Attention Neale 1/23/08
Hi Neale,
<Amanda,>
Sorry to bother you again. Thank you for your last response, I amused myself for a while imagining my future Corydoras sticking their heads into my future sand and spewing the stuff out of their gills. My last correspondence is attached below so you can pretend that you remember your previous e-mail to me :)
<Very good.>
I can see this black sand thing is going to be a headache for me (in a good way, sort of, well for my husband at least, as it seems it will keep me busy with this tank for a while, which means I won't be wanting another one....for a while).
<Heh!>
This black silica 'sand' that I found, I am now not convinced is what you were talking about or even what I thought it was. I am now even debating if they should be calling it sand. I bought a small bag (didn't want to jump in all at once), took it home and opened it. I had read earlier that day (apparently black sand is all the rage at the moment here on WWM) that I wanted to make sure the sand wasn't sharp, which means if I feel it; it feels silky smooth...not scratchy. Well this is about the un-smoothest (I know it's not a real word) 'sand' I've ever felt.
<Sounds as if this is "sharp sand", used in horticulture to improve drainage. Good for plants, not good for fish.>
Secondly, I'm not convinced it's sand, and it's certainly not 1mm (would really like to know who was doing the grading for that and what they thought a mm is). It's all irregular looking, with sticky outie bits all over it and I'm sure I could poke my own eye out with it if I wasn't careful. Then there are the needle like bits I can honestly envision the needle like bits in the bag impaling a small fish.
<Doesn't sound like what you want. Save it for the houseplants...>
Now to me sand is the stuff you find on a beach or in a river bed, stuff that's fairly fine and gets stuck in uncomfortable places and drives you insane because the more you brush it to get it off the more places it spreads to. It's not some rough pokey outie weird stuff that you couldn't imagine a Corydoras burrowing through without impaling itself on or getting it caught in its gills and suffocating to death. Am I just being woefully ignorant of what type of 'sand' I am searching for?
<You're correct: the sand suitable for use in an aquarium needs to be of the type called "smooth sand".>
Should I be looking for beach type sand (imagine the beaches in
Australia and the type of sand there) or is this sticky outie stuff "it".
<Beach sand is normally a mix of silica sand and pulverised seashells; while it looks really good in aquaria, the problem is that it raises the carbonate hardness of the water, which in turn raises the pH. These two changes are not always acceptable. Corydoras and tetras, for example, prefer water that's on the acidic side and soft to moderately hard. So beach sand tends to be a better choice for fish that like hard water conditions, such as livebearers. Mbuna and brackish water fish. River sand is variable: some river sands are identical to beach sand in being a mix of silica and lime, but others are purely silica and work great in aquaria.>
I just really don't want to get something that will make my Corydoras (when I finally get the tank set up and decide what specie to get) unhappy, or even potentially hurt them.
<Correct. Which substrate you use has a huge impact on how an aquarium looks. Although one of the less expensive parts of the set-up, the differences in terms of aesthetics between different substrates are huge. If all else fails, plain smooth silica sand (sometimes marketed as silver sand) works fine, and it's what I use in my tanks. Yes, it is bright and very reflective, but if you tint the water with blackwater extract (or put peat granulate in the filter) this can be toned down a bit, and once the plants and algae have done their thing, it looks very nice. The fish don't really care about the colour of the sand; it's more how the fish look to our eyes.>
I get frustrated at times as things that seem to be quite common in the States and the UK are just about impossible to find here in Australia (don't even get me started on how long it took me to source Selcon....and then the price....I hope my fish appreciate what I go through for them).
<I'm sure the right sand is available (and cheap) in Australia. Silica sand (silver sand) is such a basic commodity that you'll eventually find it. It's used a lot in indoor and outdoor gardening. Some people have apparently also got this kind of sand as "play" sand. So garden centres are usually places to find it. Black aquarium sand is always more difficult to find and much more expensive, at least here in the UK, where the price is something like 5 or 10 times that of bulk silver sand. For what it's worth, there are some superb fishkeeping clubs in Australia, such as ANGFA, and they may be able to help you as well. I'm always incredibly jealous of my Australian fishkeeping friends because of the terrific stuff they get to keep. Your native fishes are amazing, and only very rarely sold in Europe.>
Thank you.
Amanda
<Cheers, Neale.>

Freshwater silica sand/substrate question(s) 1/19/08
Mates,
<Hello,>
Thanks for the all the help in the past and, generally, for keeping this site active and (extremely) useful.
<Cool.>
I am setting up a 120g freshwater tank, to house rainbows, Congo tetras, various Plecos and a few Corys.
<Hmm... be careful with the "various plecs" idea -- not all of them play nicely together.>
I've got them all in a 50g right now, with HOB AquaClear (way oversized for current application), silica sand substrate from home depot, healthy amount of Mopani wood and some lace rock. A few freshwater plants for decoration...java moss and water lettuce. Everyone is happy. No casualties at any time...been good for about 9 months now. Plecos have been much less nocturnal recently...to me, a good sign they are starting to feel comfortable in their current home.
<Indeed.>
On new tank (don't know if it matters, but I'll give it out anyways), planning on dual internal overflow boxes from glass-holes.com with 1.5" holes on both, sump below with filter sock for mechanical filtration, FBF for biological (don't want bio-balls/bio-bale...too much commotion and trying to avoid as much CO2 loss as I can...it will be moderately planted with primarily low input plants...FBF just seems like the best fit), return pump either an Eheim submersible or pan world external. 240w t-5 full spectrums. I am planning on keeping plants on Mopani driftwood (like Anubias, java moss, java fern) and in pots, probably not going to drop anything directly into the substrate.
<My feeling here is CO2 is a waste with very slow growing plants like these. Their growth is slow enough the ambient CO2 in plain water will be adequate. As you probably know, CO2 is something you need to add to brightly-lit tanks because the fast-growing plants need the CO2 for photosynthesis to keep up with amount of light. Your selection of plants live in shade and don't like a lot of light (Anubias tends to get covered in algae). Java fern also seems to thrive in hard, even brackish, water and likely removes carbon from bicarbonate in the water anyway. Since CO2 is toxic to fish if not dosed carefully, I'd balance any benefits against the potential risks.>
This tank will probably be converted to reef tank in a few years...trying to plan for that during freshwater set up, but treat the freshies appropriately now. (Any other suggestions/warnings on the set up are appreciated).
<Above.>
Anyhow, I realized this week how much substrate it was going to take to fill up the tank. It is about 8 square feet...at 3" deep, that's about 2 square feet of substrate. That is a ton (well, not literally). Probably in the neighborhood of 150lbs of sand. For river sand/cafe sand/beach sand, that is gonna be around $160 at the local LFS.
<Yikes!>
Now, as mentioned above, I've used the #30 silica sand from home depot. it is just listed as industrial sand, but states on the back purity in excess of 99.?% silica sand. I've used in two tanks with Corys, Plecos, aquatic dwarf frogs, and never had any issues (no casualties, no evidence of barbel/gill/skin/scale damage of any kind), other than it takes for ever to rinse and about a week to clear up once it is in the tank. I read in the Neale Monks article (great name by the way - "Nice Bottoms") that you have to watch out for 'sharp' silica...I have no idea how to tell if it is sharp or not. Can you help me on this?
<Sharp sand is a specific grade of sand used in horticulture at least for providing good drainage in potting compost mixes. It's also used in building work of various kinds. The grains are angular rather than rounded, and it feels sharp or scratchy to the touch. Smooth silica sand, the kind used in aquaria, has a lovely silky feel.>
As well, there are two different grades - #20 and #30. I combed through the internet (got to love google) but couldn't really find an explanation as to grades and granule sizes. From what I could gather, #20 granule is bigger than #30 granule. Is this right?
<No idea. Provided the sand is smooth, the size of the grains couldn't matter less really. I suppose bigger sand grains would be better in some ways, since they're less likely to get swooshed about into the water column when fish swim by. (And big fish really do kick the stuff up into the tank!)>
Obvious, I'd want to go with the largest granules I can get to minimize dangers of compacting/anaerobic decay/nasty gases.
<This issue at least is largely irrelevant. Anaerobic decay is a bit of an exaggerated problem. If you're not planting anything, then you don't really need much sand anyway. In deep sand beds, any anaerobic decay mostly breaks down nitrate (a good thing, encouraged in marine tanks!) and any H2S produced reacts virtually at once with oxygen should it get into the water column and has little real impact on fish health. Go visit a pond and see how much anaerobic decay there is there... and yet the fish are fine.>
Last, and off topic but something I've always wondered, would a protein
skimmer provide any benefit to a freshwater set up?
<Generally no. A standard skimmer requires a certain amount of salinity to work at all. Brackish systems at SG 1.010 seem to be about the minimum. If the salinity is too low, the bubbles don't stick together and you don't get the froth. There are freshwater skimmers, but they're rather different (and bigger) and used primarily for ponds. Besides, in a freshwater system, water changes are so cheap that you may as well use them for nitrate control. Few freshwater fish are particularly sensitive to nitrate, so provided you keep things below 20 mg/l, you're fine, even with Discus or Tanganyikans. By contrast, marine aquarists generally want to maintain much lower nitrate levels than that. Bottom line, there's no particular need for skimmers in freshwater tanks.>
Thanks. Paul in San Diego.
<Cheers, Neale.>

BGA/silicate connection 11/9/07
Hi guys, Scott here.
For the second time in about a year, I am battling BGA in my 20-gal freshwater tank. The tank is heavily planted, with a 65-watt Corallife compact fluorescent fixture. The bulb is about a year old. Java fern, Java moss, Wisteria, A. nana, corkscrew vals, and something I think is a variety of crypto are all producing new growth without CO, and little supplementation. Rotala indica not so well, but still has new growth.
<Sounds like insufficient light. Rotala is a plant that is a weed under bright light, but does nothing at all under inadequate light. For example, I've stuck this species in a garden pond and it has survived and grown even under ice! But inside moderately illuminated aquaria, it just slowly dies. If light isn't the issue, check the substrate and CO2 concentration: both of these are key factors for Rotala.>
For some reason, the rhizomes of my banana plants rotted away, but they continue to produce new growth.
<Hardly the most reliable plant in the hobby. They need very specific water conditions depending on the species in question. Seemingly little adaptability.>
The main problem has been BGA that grows over the lower leaves and chokes them off.
<Common problem. Water quality (nitrate and phosphate especially), overheating, and direct sunlight are all critical triggers for Blue-green Algae. Often, treating with antibiotics is the only quick way to completely eliminate BGA, but if you get good plant growth and stabilise water quality, eventually it fades away.>
I am using straight well water, which I have tested for silicates at around 10mg/l.
<Silicate isn't really an issue with Blue-green Algae. Diatoms perhaps, but even in freshwater aquaria Diatoms aren't normally a problem except in immature tanks or tanks with poor lighting.>
Sometime in the last few months, the pH of my well seems to have increased from 7 to around 7.4. The tank tests between 7.4-7.8. Phosphates are under .25. One of my local LFS insists that the silicate is what is feeding the BGA.
<No, it's really not. Silicate is hardly used by most organisms. Diatoms almost uniquely use silicon to produce their external "shell".>
I am considering an R/O unit, because I also have some funky-looking stuff growing in my saltwater tank. I guess the main questions I have are: Is the silicate likely the BGA culprit, and if so, will an R/O unit make that much difference?
<Reducing the phosphate level in the water may help, but the silicate is hardly here nor there. In freshwater tanks, the way to beat algae is stunningly simple: fast-growing plants. Hygrophila, Cabomba, hornwort, etc all work well. Slow-growing species like crypts and ferns have no effect. The theory is that fast-growing plants produce chemicals that suppress the growth of algae. In my experience, this method works well, even against Blue-green Algae.>
The silicate test I use states that silicates are not an issue for freshwater tanks and will usually be between 4-20mg/l. If I go to R/O water, will decomposing plant material leach silicate back into the water anyway, and if so for how long?
<Most plants contain very little silicon; the exception are grasses, which deliberately use silicone to prevent grazing (and this is why grass-grazing mammals have rapidly-growing teeth -- the silicon is constantly wearing them down). Hope this helps, Neale>

pH Level While Using Red Sea Floralbase 11/07/07
Hi,
I have recently set up a new 72gal FW tank. I have had water in it, Rena xp3 filter, heater, and Corallife 65watt x2 for lights. I presently have 15 goldfish in it to help with the cycling.
<<A poor idea. Too much stress and likelihood of parasitic infestation... RMF>>
My ph level has been at 6.0 from the start. I am using red sea Floralbase, that's all, as I have a planted tank. I am wondering how to raise the PH level to at least 7.0 for the types of fish I want (I have a 10gal that has been established for 2 years now & I would like to take those fish and move them over to the new one, that PH has been 7.0 - the fish in the 10gal is neon tetra, black skirt tetra, 2 Danios and 1 Chinese algae eater). Is there some sort of PH up that I can use safely? I do have several kinds of plants. My ammonia, nitrites and nitrates are all within the proper range & are great.
Thanks
Kim
<Hello Kim. Two things here. Firstly, what sort of fish do you want to keep? An acidic pH of 6.0 is actually very good for a wide range of species. Most South American fish will thrive here, as will most of the fish from Southeast Asia. Secondly, you need to clear up the difference between pH and hardness in your head. Fish don't "feel" pH directly and don't really care about it all that much; what matters is how much mineral content the water has, because this is what has an impact on osmoregulation (how they balance salt and water in their bodies). So, what you want to check first is the hardness of your water now, and the preferred hardness of the fish you want to keep. I'm guessing your water is quite soft (i.e., a low hardness around 5 degrees dH). That's fine for tetras, angelfish, Gouramis etc. But if you want to keep livebearers or Rainbowfish, they need a higher level of hardness, at least 10 degrees dH and ideally well above that for livebearers especially. Once you take care of hardness, then the pH will adjust itself pretty well automatically. Hard water tends to have a high pH, and that high pH is pretty stable. There are various ways to raise the hardness. The simplest is to incorporate some calcareous material into the filter. Crushed coral is one such medium. As the water washes past, the coral dissolves, raising the hardness. Periodically you clean the coral to wash away slime that coats it, and maybe once a year replace it with a bunch of new coral. There are other methods too; any aquarium book should discuss them, but if you want some more ideas, let me know. Cheers, Neale.>

Just a question... Rocks from the beach, use/FW  – 09/14/07
Hi I own a ten gallon tank and I found some stones on the beach and was wondering if I could put them i the tank? I have platies and tetras. If I
can put them in what are the procedures for doing so?
<Depends on the stones. If they're non-soluble, non-porous things like granite or flint, then simply washing well with hot water should make them adequately safe. Anything soluble, like limestone or coral, is less useful because these will change the pH and hardness of the tank (to test, add some acid: if there's fizzing, the rock contains lime). The platies won't mind, but the neons will. So these sorts of rocks shouldn't be used. Porous rocks, like pumice, are generally best avoided because anything dead in the holes can decay in the aquarium and pollute the water. If in doubt, leave the stones out and just use ones bought from a tropical fish store. In a 10 gallon tank especially, hollow ornaments would displace less water and create hiding places for your fish, particularly baby platies. As such, they'd be much better value. Cheers, Neale>

Re: Just a question... testing FW substrates  – 09/14/07
Thank you Nelle, but how long should I soak them in the vinegar for? I tried and only one to three bubbles came up, so I put them in the tank is it alright?
<No, you don't soak in acid. You add acid (like vinegar) and if there are bubbles, that means the stone contains lime. Lime + acid = carbon dioxide. The conclusion is you CANNOT use this stone in a freshwater aquarium. If you put it in the aquarium, it will slowly dissolve raising the pH and hardness. Cheers, Neale>

Coarse Sand VS. Course Sand 9/5/07
Hi there! I like that you are sticklers for proper grammar and spelling, but I would like to point out something that I have repeatedly run across the last few weeks as I am thoroughly researching before setting up a 92-gallon corner tank. Many times when I read about sand size, the mention is for "course" sand. This is not only in your articles (sorry Anthony and others), but also in several books and magazines. However, my understanding, esp. after verifying this in a dictionary, is that it should be "coarse" - or am I missing something new in aquarium technology? I thoroughly enjoy all the articles on your website, and am thoroughly impressed with the breadth and depth of everyone's knowledge...so I hope either I am wrong in this term or it will correct some incoming questions' spellings. Thanks tremendously, Kerstin DeRolf:-)
< According to the United Soil Classification System Method ASTM D 2487 the correct spelling is "coarse". Soils are classified and sold based on the size of the individual particles and percentage of each. The local fish store buys coarse sand from the quarry and should call it the same when it is sold to aquarists.-Chuck>

Changing Substrate in a 75 gallon FW 7/15/07
<Hi, Pufferpunk here>
I am wanting to change the substrate from my 75 gallon FW from gravel to sand.
<Why? Do you have burrowing fish? Sand in a tank that size is a real PITA, as it needs to be thoroughly stirred weekly, to prevent anaerobic pockets (toxic gasses) from forming & killing your fish. In a tank that large, it would become tiresome after a while.>
I am wondering what the best method would be to do this, and I am also wondering what the best type of sand to use is? I have that play sand is the best to use because its sterile. Is that true?
<Many folks do use play sand for their tanks. Like I said before, I wouldn't bother. Just my opinion. But if you insist--move everything out of the tank & remove all the gravel. Then slowly pour in the well-rinsed sand. It will cloud up for a while. You can try removing the floating particles but adding filter floss to the filter & changing it after it gets clogged. Keep an eye on the parameters. You will be removing a huge chunk if nitrifying bacteria, which may cause a mini-cycle. You can add Bio-Spira to replenish the bacteria. Do not add any other product, than Bio-Spira! Good luck with whatever you decide. ~PP>
Thanks in advance for your response.

Freshwater deep sand bed experiments   7/2/07
Your website alludes to some experiments that were to be done about nitrate reduction using deep sand beds in a freshwater system. Any results available?
<Mmm, w/o a "trip" to the/a large library here with access to computer bibliographic search... I can only state from vague memory (nothing in my hard files) that I have seen articles in other languages (German, French, and likely Italian and Japanese) re this phenomenon. There are discernible "effects", practical implications of DSBs, use in FW aquariums>
There are a couple of problems I could see. The marine sand beds are dependent on sand sifters and burrowers
it sounds like,
<To a larger extent... the variability in the make up physically, chemically, biologically... of such disparate "habitats", marine, freshwater and otherwise is huge... Suffice it to state that many FW bodies have significant infaunal populations. I suggest perusing a limnology text...>
to move material around and prevent excess stagnation and hydrogen sulfide production, according to some web site sources. Maybe no such organisms are available for freshwater systems.
<Mmm, perhaps not yet... but like marine "live substrates" these can be made pretty easily...>
Do the sand beds really work for freshwater? Particularly for a soft water (Amazon) tank....
<Mmmmm, interesting thoughts... IF one could receive a starter inoculum... or even just some "muck", what have you, from an importer of... plants from this region... Bob Fenner>

Freshwater deep sand bed  7/5/07
I was wondering if the "experiments" outlined below by Magnus (a previous WWM discussion) have had any results yet. The deep sand bed idea in freshwater seems questionable, partially because of the lack or less sand sifter organisms available. Some sources, including the freshwater substrate article on your WWM site, caution against anaerobic pockets causing poisonous by-products.
<Greetings. I can't comment on Magnus' work, so I'll leave Bob to fill in there. But I do have some thoughts of my own. Freshwater aquarists are quite well served with sand-sifting organisms. At the top level you have fish: catfish, spiny eels, loaches, etc. that will continually sift or burrow through the top few cm of the substrate. Going a little deeper are things like Malayan livebearing snails. Oligochaetes like Tubifex could potentially work, but the problem is most fish would eat them. Finally, you have plant roots. Aquatic plants transport oxygen down their roots via special air channels. This allows the cells in the roots to survive even in the anaerobic mud where plants extract the minerals they need. So while it is potentially possible for anaerobic conditions to develop in a freshwater aquarium, in practise it is relatively uncommon. I've used relatively deep sand substrates (up to around 15 cm) in freshwater tanks on and off for 15 years, and never yet seen any signs of toxic anaerobic decay. This isn't to say it can't happen, but in a well-maintained planted aquarium it seems to be a low risk problem.>
The Deep Sand bed does have the same ideas in freshwater as in SW, the dense area is devoid of O2 so the bacteria can set up home, and start working on the waste. And it seems having that and a nice mechanical filtration on a freshwater tank does seem to be as beneficial to the health of the tank as it does in the world of salt. In fact I'm dealing with a aquarist in PA who is currently trying to study the benefits of DSBs and other properties in the freshwater world. Hopefully we make some nice findings with our studies, and help the freshwater world.>=>(I have a pond in the garden that is heavily grown with algae and water lilies, and teaming with guppies and rams for almost a year already. The substrate is about 3 inches thick. Could this be considered a DSB?)<I really wouldn't consider it a DSB, I consider anything over 4-5 inches deep as sand beds go. In freshwater ponds, the sand is a great host for many insect larva, that act as the clean up crew in oceans... The only problem is that these larva grow up, and turn into large stinging/biting/scary looking adult flying insects, so we can't bring them into the home aquarium. Sounds like you have a healthy pond there! Good luck. -Magnus>
<Your observation of the pond situation is important. In practically all freshwater habitats, anaerobic conditions exist below the surface of the substrate. In lakes, anaerobic waters exist below a certain depth because of the lack of water current. (In the sea, by contrast, water currents exist at deep levels because of the cold water flow from the Arctic and Antarctic, reaching as far as the equator.) Anyway, aquatic plants *depend* on the anaerobic conditions and cannot do well without them. Oxygen-rich mud converts mineral ions such as iron from the reduced to the oxidised state. Plants can't absorb the oxidised state. This is why plants have evolved that oxygen transportation system mentioned earlier. If you look at aquatic plants under a microscope, you will see they are very spongy, and its those holes that allow the oxygen to travel down to the roots. As is so often the case with plants, their solution to this problem is simple, elegant, and very efficient.>
Versus these cautions elsewhere on your site:
The use of deeper and or finer grades of substrate are used to anaerobically ("without oxygen") convert nitrates back to gaseous nitrogen for removal from the system. There are definite benefits and dangers in these approaches versus the use of live plants, water changes, and chemical filtrants… to alleviate nitrate accumulation. The potential downsides of this anaerobiosis are production of noxious by-products like hydrogen sulfide gas (rotten egg smell), which can be deadly.
<My gut feeling about nitrate removal in freshwater tanks is that attempting to use a DSB is probably not really worth the effort Admittedly, I haven't yet seen H2S develop in a freshwater tank. Furthermore, while I have seen gas bubbles in deep sand substrates, these seem to be harmless, so are presumably nitrogen or possible oxygen from the plant roots. But there are simply much better ways to remove nitrate in a freshwater tank. Water changes for one thing are so much cheaper and easier. If you have fish adapted to your local water chemistry (the ideal situation) then you can do water changes as often as you have time! Secondly, plants are fantastically efficient nitrate and phosphate removers. If you have fast growing species like Cabomba, you are cropping them back weekly, so effectively running a "vegetable filter". Finally, freshwater fish are largely nitrate tolerant. The oft-quoted but still instructed statistic is from lab work on trout, which are 1000 times more sensitive to ammonia and nitrite than they are to nitrate. For a standard community tank without nitrate-sensitive species nitrate level of 50 mg/l is fine, and even up to a 100 mg/l is unlikely to cause problems. In special cases, as with discus and mollies, you need lower levels, and Tanganyikan cichlids especially are very intolerant of nitrate. But neons, Corydoras, angelfish, gouramis, etc. are indifferent to all but the highest levels of nitrate. This contrasts with the situation in marine fishkeeping where nitrate is more or less toxic to the species being kept. Even a fish-only system wants something less than 20 mg/l, and reef tanks practically no nitrate. The zooxanthellae in the corals don't use up nitrate at anything like the rate of fast-growing plants, so coral growth isn't a significant nitrate dump. Hence the value of DSBs in marine tanks. Anyway, those are my thoughts. I'm sure Bob and others may have ideas as well. Cheers, Neale.> <<Scant few. RMF>>

Question about sand and filter impellers – 06/11/07
Hello everyone,
<Hello.>
I have a question about sand's effect on hang-on filters. I added some extremely, extremely fine sand to my tank (it's by Zoo-Med, called "Repti-sand"). It's made of quartz and is very, very fine and light, so much that it took about 2 days until the water was clear after I added it to the existing tank. Really, it's more like dust than sand. Anyway, I have four emerald Cory's in there now, and they love scooting around in it and it's very soft so it's easy on their bodies. It also hasn't affected my pH. I've had it like that for about a week and a half, and then last night the filter started making some grinding noises, so I pulled it out, rinsed it out (some sand came out) and tried to get it to work a few times. Then I looked online and read about impellers, and I saw that the impeller was broken (its blades go around and around). Do you think it's the sand that caused it, or my jiggling it around and taking it apart a few times trying to get it to work, perhaps not being gentle enough, that did it? That one was a Penguin Bio-wheel, and I got a new one today, an Aqua Clear with the different style of filtration. This one's making kind of a gritty noise as well, and I'm afraid it will break, too. Is this a common problem? Do you think I should get rid of the sand, or at least get some heavier sand that isn't so easily disturbed and sucked up into the filter? I do want to keep some sort of sand because I want to get kuhli loaches later on.
<Sand can damage the impellers of pumps. It isn't common though. I use silica sand in all my aquaria, and while sand sometimes gets stuck inside the filter canister, it doesn't seem to do any harm. But your own mileage may vary! Silica sand in particular is quite heavy and settles very quickly. The only time it gets into the water column (and thus into the filter) is when a big catfish decides to swish into the sand and dig herself a burrow. Small things, like Corydoras, simply don't push the sand far enough off the substrate to cause problems. Now, if sand gets inside the impeller, it can quite possibly cause some rattling noise. In the long term, anything that clogs filter media forces the impeller to work harder, and puts all its components under more stress. You probably want to make sure the filter inlet is far enough above the substrate that the fish can't swoosh the sand into the filter. Adding a decent pre-filter layer to your filter system (such as filter floss) is also a good idea. My gut feeling is that while silica sand has been used for many years by many aquarists without problems, finer sands like your Repti-sand might be just a bit too fine for safe use.>
Thanks for any and all help you can offer! I really appreciate it!
Allison Evans
<Hope this helps. I'm a BIG fan of sand in aquaria, and agree with you that loaches and catfish really benefit from its use. But it does need to be handled properly. Cheers, Neale>

Reefbase Coral Sand for FW use?    5/14/07
A friend of mine just got a new saltwater tank and it came with a starter kit – Sand, chemicals, etc. The sand is Reef Base (made by Red Sea ) Crushed Coral and I was curious if I could use that in a freshwater tank.
Thanks,
Tony Zucarelli
<Can be... if the livestock you intend to keep likes/tolerates hard, alkaline water... the CaCO3 will continuously dissolve... Useful for some types/biotopes... Please read here: http://www.wetwebmedia.com/FWSubWebIndex/fwsubstrates.htm
and the linked files above.
Bob Fenner>

Quick questions about recovering from ammonia poisoning, and necessity of gravel  (Neale's go) – 04/22/07
Hi Crew,
<Hello!>
I have two quick questions--I had an ammonia problem a month or so ago (100% taken care of now) and I was wondering how much this has reduced the life span of fish that have survived...is the damage permanent or can they recover completely? Do the damaged cells regrow or are their gills permanently compromised?
<In theory I suppose its possible that some damage was done, but don't worry about it. Fish are surprisingly good at healing damaged tissues, certainly much more so than humans. They routinely grow back fins and even quite substantial flesh wounds.>
Also, do you have any resources I can look at regarding whether gravel is necessary for a fish tank?
<Interesting question. Gravel as such isn't essential, and it is quite common not to use gravel at all in certain aquaria, such as breeding tanks and quarantine tanks. However, most fish object to having no substrate underneath them *if* the glass is left shiny and bare. Fish *do not* like light coming from underneath them.>
I have a bio-wheel and bio-balls for the bacteria, but does your average Cory catfish need it to feel at home in the tank?
<Corydoras far prefer soft non-calcareous sand. That's how I keep mine. They keep it spotlessly clean, and you only need half an inch depth. They plough into it, spewing the sand out through their gills while they hunt for food. It's adorable!>
I think it's easier to keep the tank clean if you have no gravel to get the food stuck in, but I'd put it back if the fish actually miss it.
<If you have a thin substrate of sand it won't get dirty. Sand is too compact for faeces and food to sink into, and the catfish will turn it over constantly removing any live foods that might wriggle into it. I find sand actually easier to keep clean than gravel. The downside is that it can get sucked into the filter if you have large fish swishing the sand into the water column with their big tails (my Panaque catfish does this all the time!).>
Thanks for any help you can offer!
<No problems. Neale>
Allison

Quick questions about recovering from ammonia poisoning, and necessity of gravel (Tom's go) – 04/22/07
Hi Crew,
<<Hi, Allison. Tom with you.>>
I have two quick questions--I had an ammonia problem a month or so ago (100% taken care of now) and I was wondering how much this has reduced the life span of fish that have survived...is the damage permanent or can they recover completely?  Do the damaged cells regrow or are their gills permanently compromised?  
<<Good question, Allison. First, fish can certainly recover from a tangle with ammonia exposure/poisoning but, to hedge my bets here just a little, it would depend greatly on how big the problem was that we’re talking about. A minor exposure would likely cause the gill tissues to become irritated and, perhaps, somewhat swollen. Stressful, of course, but not irreversible. Moderate exposure would certainly cause the gill tissues to swell resulting in hampered breathing and reduced excretion of ammonia – through specialized gill tissues – from the body. Skin, eyes and gills would likely be irritated to the point of potential damage. If concentrations of ammonia were to build up to significant levels, internal organs would be irritated/damaged. A major “episode” would render the question, pretty much, moot. The fish would either die of suffocation or internal poisoning from ammonia build-up. Even if the fish didn’t succumb immediately, the damage could be so severe that it would be best to euthanize the animal.>>
Also, do you have any resources I can look at regarding whether gravel is necessary for a fish tank?  I have a bio-wheel and bio-balls for the bacteria, but does your average Cory catfish need it to feel at home in the tank?
<<Sure! Us. To start, remember that nitrifying bacteria inhabit all parts of the tank and the substrate is no exception. Gravel will, of course, provide more “surface area” for the bacteria so, from that perspective, it does provide a useful service. (One that shouldn’t be under-emphasized, I might add.) Now, to what I think you’re really getting at, no, you don’t “need” gravel/substrate in your tank. Corys are non-stop scavengers and will do so with, or without, gravel in the aquarium. In large part, its use is for aesthetic reasons only. People typically don’t like bare-bottom tanks. Fish couldn’t care less, by and large. Yes, there are some fish that lay eggs in “nests” in hollows in the substrate but I don’t think that’s your point here.>>
I think it's easier to keep the tank clean if you have no gravel to get the food stuck in, but I'd put it back if the fish actually miss it.
<<Your fish won’t “miss” gravel, Allison. Corys will stay just as busy in a bare-bottom tank as they will in a tank with gravel in it.>>
Thanks for any help you can offer!
Allison
<<I hope did help, Allison. Any more questions? You know where to find us. Best regards. Tom>>

Changing rocks in an established tank  - 03/10/07
Thank you so very much for your time and help with my occasional questions.
My fish and I appreciate it. Hopefully this one is a very quick one.
I'm bored with the current color of the gravel rocks in my aquarium, so I bought enough bags of a new color to replace the old ones with. Are there any concerns I should be aware of before making the switch; i.e.. Remove the fish temporarily into a container while doing the change?
<<Catching on your fish may prove more stressful than working around them, especially if it is pebbles and not cloudy.  My only concern might be the amount of your bio-filter that will be removed with the substrate.  Might be prudent to remove in smaller amounts over time.>>
When opening the bags of gravel rocks, should I wash them first?
<<Rinsing will do.>>
Should I put a new filter in my tank (old one is okay, but just want to be safe)?
<<Not unless you want a new/additional filter.>>
Are there any additives or extras needing to be put in the water?
<<Aside from dechlorinator, no.>>
This is my first ever tank which I set up about one year ago so is well established, no unusual deaths (not counting the live fry eaten by the parents). Been using a product called Nitraban,
<<No need to use this in an established tank.>>
Do partial water changes regularly to keep from nitrate build up.
<<Partial water changes are key to a healthy tank. Keep it up.>>
and about once a week drop in an anti-ammonia dissolving tablet just in case.
<<This is not beneficial to your tank.  Nitrifying bacteria feed on ammonia, and your tank is well cycled, so no ammonia should be readable; these tabs aren’t necessary.>>
The youngest fry are currently 2-3 months old -unless I have more hiding somewhere since I keep abundant decor so everyone can hide if they want. Also, my tank is in a room in an underground basement, so it's impossible for any outside light to get in. I don't have a bad problem with algae, but noticed it builds up faster the longer I have the tank light on, often for several hours per day. Tank is by the computer and I really enjoy them, and named most of my fish. I've read that using anti-algae formulas will do something that "starves out oxygen" in the tank. Is this true?
<<Can be, are often hard on biofiltration, and ignore the source of the problem. I am not a fan at all.  Try limiting the hours the aquarium light is on.>>
I do have an aeration pump.  I've just been cleaning the fake plants and decor by hand and discarding the filthiest of rocks, hence a part of the reason I want to dump the white rocks and put a new color in also. I've already read mollies are a vegetarian type of eater, so am I right to assume it's okay to leave some algae on plants to allow them to peck at?
<<Not strictly vegetarians, but certainly need lots of vegetation in their diet.  It is best to leave some algae for them to pick at.>>
My Corydoras I read are carnivorous and blood worms are healthy for them.
The mollies enjoy them also. Are blood worms healthy for mollies?
<<Can be part of their diet certainly.  Do be sure to offer all of your fishes as varied a diet as possible for optimum health. Lisa.>>
SK