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Converting Saltwater to Freshwater (Af. Cichlids...)
Switched SW to FW (cichlids)
converting from marine to fresh water
I have at last decided to change to fresh water. Mainly due to the crazy costs of electricity, fish and corals. Rather than close down completely I thought that converting to fresh water would be a better option in terms of monthly expenses?
<Yes. I recently did a piece for Practical Fishkeeping magazine in the UK on the cost of fishkeeping. I added up the cost of buying a 125-litre (~30 US gal.) aquarium, a heater, filter, and lights; stocking it with community fish and plants; decorating it; and paying for food, water changes and electricity across the next 5 years. The overall cost came out at just over Â£650, about $1000. Of that, more than half was buying the hardware, with only about Â£250 coming from running expenses like electricity, and that's over 5 years remember, so that's about Â£50 a year. The UK is a relatively expensive country, so your own costs may be somewhat less depending on where you live. As it happens, the PFK website used to have a nifty tool for calculating the running costs of your tank. It's still there, but you do need to subscribe to the website, which is free:
Briefly, I have a 2000L tank with a 700L sump. Water also flows through 2x 100L deep sand bed refugiums. The system runs off 2x Reeflow pumps, one for the main recycling through the skimmer and sump with the other providing the water flow in a closed loop system. Total tank turn over probably about 10x. Two smaller pumps run the skimmer and calc set up. I removed my halogen lamps some time ago and only use T5 tubes. While the Reeflow pumps run more efficiently (than the previous pool pumps) they also generate less heat so now I have a problem in winter with my water dropping to 21C but great for summer at 26C. So the reverse now takes place with me trying to heat the water instead of cooling it in summer!! Back to square one. I also made a decision a year ago to simply stop adding chemicals to the water. Not much changed although to be fair I had stopped buying corals at that stage. Although I have been able to reduce my running costs by about 25% it is still way over the top with this tank costing me about the equivalent of 7000USD a year!
<This does sound rather a lot!>
I would like a colourful tank full of a variety of smaller fish, max 100 mm in size.
<A lot will depend on your water chemistry. Assuming you don't want to go down the avenue of buying or making RO water, then you want species that enjoy or at least tolerate your tap water chemistry. In the case of soft water, pretty much anything from South America, West Africa and Southeast Asia will work, with tetras, Rasboras and barbs being among the more brightly coloured species. In the case of hard water, Central American livebearers, East African lake cichlids, and Australian rainbowfish offer the better options. There is some overlap between the two groups, but for the most part understanding these two sets of water chemistry is the best way forward. If you have middling water chemistry, ~10 degrees dH, pH 7-7.5, then you can mix fish from both sets of water chemistry without problems except in a very few sensitive cases (Mollies for example really need very hard water, while Ram Cichlids don't do well in anything other than very soft water). So, tell me your water chemistry, and we'll discuss further, if you want.>
Plants and various rock or ornaments creating interesting shapes and swim throughs for the fish.
<Strong lighting is useful for the greatest variety of plants, but in all honesty, the importance of carbon dioxide fertilisation in general purpose fishkeeping has been much overrated. If you have something like 1.5-2.5 watts/gallon, or 3-4 fluorescent tubes running the full length of the tank, then in all likelihood pretty much any hardy plant should do well, and a good starting point is Vallisneria and Amazon swords for the background, Anubias and Java fern as specimen plants on bogwood and rocks, and hybrid Crypts and hardy species like Cryptocoryne wendtii for the corners and sides. That's a good mix of undemanding plants that tolerate a broad range of water chemistry and light intensities. You can get a cheap "reef tank" feel by adding small invertebrates -- Cherry Shrimps and Nerite snails are excellent algae-eaters, while Clea helena and Tylomelania snails are fun scavengers and don't breed quickly.>
Since I have "most" of the equipment I imagine that all I have to do is choose the right type of fish and plants to achieve my goal. Could you also indicate which equipment could be used for the new set up.
<Marine-grade skimmers aren't strong enough to work in freshwater, and anything that splashes water, like a trickle filter, will remove CO2 from the water and neutralise the usefulness of CO2 fertilisations. UV sterilizers work as well in freshwater as salt, so you can keep them if you want, perhaps switching on for a couple of weeks after introducing new livestock. Calcareous rock such as tufa and "dead" live rock work fine in freshwater, but will of course raise the pH and carbonate hardness, so are used in seriously hard water situations, livebearers for example, or Tanganyikan cichlids (these latter, incidentally, making excellent alternatives to reef fish, being very similar in shape and habitats -- see for example Neolamprologus leleupi and Neolamprologus tretocephalus. Malawians are good in this context too, but usually a step-up in aggressiveness. Light intensity can usually be half or less compared to an equivalent size reef tank except where the most demanding plants are being grown. Algae is a problem in brightly-lit freshwater tanks, and is best managed through fast-growing plants and algae-eaters, particularly Nerite snails, shrimps and, with care, certain fish.>
Perhaps I am asking for too much but I would like an exciting colourful visual display which is simple to maintain ( I travel a lot) and cheap to run.
Your help would be most appreciated.
Re: converting from marine to fresh water 7/29/11
Thanks so much for the quick response! Will digest and get back to you.
<Glad to help. Cheers, Neale.>
Saltwater to Freshwater
Re: Saltwater to Freshwater
75 gallon aquarium, Salt to Freshwater Conversion
Converting from saltwater to freshwater Tank
Re: Converting from saltwater to freshwater Tank
Saltwater to Freshwater Conversion -
Re: Saltwater to Freshwater Conversion -
Re: Saltwater to Freshwater Conversion
Converting Marine to Fresh --
Changing to freshwater and stocking 6/18/08 Hello again. <Hello!> You have all been very helpful in the past with my current marine tank though I now fancy a change as the maintenance of the marine tank is taking up too much time. I have a 500ltr main tank with a 100 ltr sump running an ocean runner 3500. In the main tank I have 2 Hydor no4's to give circulation. The lighting is by was of arcadia series 3 metal halide lamps. <Apart from the skimmer, most of your marine hardware can be used in a freshwater tank with ease. The lights may be rather strong though, i.e., algae-promoting and expensive, unless you're keeping very light-demanding plants. Otherwise, scaling back to the equivalent of 2-3 Watts per gallon fluorescent lighting is ample.> As I mentioned the maintenance of the marine tank is starting to get behind due to time limits and I am looking to switch back to freshwater. That way I can do regular water changes with ease. <Indeed.> So to the point. As I have not had freshwater for a long time I am quite out of it and have tried looking though your articles only to fry my brain. <Oh?> I am looking to use the current set up but change the substrate to a gravel and completely clean out the tanks. If I leave some of the current substrate will this help cycle the tank quicker? <Not really; except in a fairly high-end brackish system, the "marine" filter bacteria will die back completely.> What would you put in the sump for fresh water, I considered just gravel and lots of plants (not sure what type yet) <The usual use for sumps in freshwater tanks is as a place to dump chemical media, specifically carbonate material for raising the KH. This is obviously useful if you're keeping fish that need hard water, such as Tanganyikans, Mbuna, Central Americans, or Livebearers. A brackish water setup would also benefit from the sump being filled with calcareous material, but adding salt to water might be just the sort of work you're trying to avoid! Some (advanced) aquarists also use them as "vegetable filters", using fast-growing plants or algae to remove nitrate from the water. Do look at the book 'Dynamic Aquaria' for info on this sort of thing. Otherwise, simply use the sump as additional filter space and fill with bio-balls or ceramic noodles in media bags.> And finally I am looking for a quite a busy community tank (the kids love watching loads of fishes shoal) but with a few interesting fishes for me. <Lots of options here. If I had a big tank with a sump, I'd definitely explore the idea of small to medium-sized Tanganyikans (lots of colours, interesting behaviour) or "rare" (in the sense of infrequently kept) livebearers such as Goodeids. Both these options would provide ample scope for an advanced aquarist to try out non-standard, non-generic freshwater fish, whilst still offering the family lots of "pretty fish" for them to watch and breed.> Any help on the above points greatly appreciated. P.S. I considered using some of the live rock as decor rock. I know it seems a waste but might as well use some of it as the LFS does not want it all. Will the rock have any benefit in freshwater of just decor. <Dead "live" rock becomes nothing more than limestone rubble; again, splendid for tanks where the fish like hard water, but really rather an expensive approach. Generic tufa rock works just as well.> Many thanks again Paul <Cheers, Neale.> Can I use a saltwater tank for freshwater? 12/18/07 First your site is great. My question is regarding the use of a saltwater tank for freshwater use. I have a 29 gallon tank that was previously used for saltwater, It has sat empty for about 6 months now. Can I use this tank for a freshwater setup? Is there anything I have to do to be able to use this? My LFS said, once used for saltwater, you can't use for freshwater. I would appreciate your input. P.S. Am I still able to use the filters also? Thanks <Hi Dawn. The short answer is yes, a marine tank can work well for freshwater fish. The long answer is that some items used in marine tanks will either fail to work or else will create conditions perhaps not ideal for some species of fish. Of the first sort, protein skimmers are the most important. They will not work in freshwater. Of the second sort, anything that raises hardness, such as coral sand and tufa rock, are useful only in tanks where the fish like hard water. So good with Guppies and Mbuna, but not so good for Neons and Angelfish. Everything else, including filters, lights, heaters will be fine. Cheers, Neale.>
Converting Reef to Cichlid 12/1/2007 Hi Bob and Wet Crew. <Ave!> Hope your all doing well. Its been ages since I emailed you wonderful people. I would like to know what I would have to do to convert my 200 Gallon Reef Tank to a Cichlid Tank? I would also like to know what equipment should I keep in the system. <Does rather depend on the cichlids being kept. If hard water species (Tanganyikan, Malawian, Victorian or Central American cichlids) essentially everything except salt and skimmer will be useful. Soft water species (South American and West African cichlids) obviously don't want limestone materials in the tank like tufa rock. Brackish water cichlids (Chromides, plus various tilapiines and cichlasomines) can be kept tanks more or less identical to marine tanks except the skimmer won't work below SG 1.010).> Tank Info...... 1 200 Gallon Main Tank (Drilled) 2) 45 Gallon Sump with Bio Balls 3 55 Gallon Caulerpa Algae 4) Skimmer 5) UV 6) Heater (I know I should still use this, but just put it as info) 7) Many Powerhead of different specs 8 Denitrifier 9)Many Marine White and Blue Actinic Fluorescent Lighting 10) 2 Pcs Send pumps - 1 x 3325 LitresPH + 1 x 2500 LPH I hope I got everything in there. <Well, obviously the Caulerpa won't work. Better simply freeze it and use as food for herbivorous cichlids. The skimmer won't work except in mid/high-end brackish. UV sterilisers work well in freshwater even though they aren't widely used. Water current is good for riverine/lake-dwelling cichlids, but the blackwater species (like Angels and Discus) won't appreciate too much current. Lighting will be very useful if you keep algae-eating cichlids (Mbuna, Tropheus, etc.) -- allow green algae to grow on all rocky surfaces freely, and these fish will graze it down almost to the rock.> Ghulam <Cichlid care is essentially very similar to marine fish care in terms of requirements for water movement, low nitrates, and in the case of Rift Valley species high levels of carbonate hardness. The big difference is you are more likely to keep groups of the same species, so breeding and social behaviour are greater issues than with marines. Do take care when selecting stock to avoiding having closely related fish: not only are hybrid fry more likely to be produced, but closely related fish often fight more than distantly related ones. There are numerous books on cichlids, and I'd encourage you to have a read of one or two of them before selecting your livestock. Hope this helps, Neale.> Re: Converting Reef to Cichlid 12/2/07 Hi Neale, Wow! This must have been the fastest email reply I ever got in my life! I forgot to mention a couple more things...hope you don't mind :-) I will be keeping Soft Water African Cichlids. What about my Live Rock (seeded from other live rocks now for over 6 years) and live sand/gravel? Shall I just vacuum everything completely? like all the shrimps and worms. Thanks and in Advance for the next email too. Ghulam <The short answer is that you will have to get rid of the sand, gravel, crushed coral, live rock, and anything else calcareous. Soft water cichlids should be kept in tanks that contain only non-soluble rocks, such as slate and granite. I would hope you can sell/give-away the live rock in its "live" condition. It goes without saying that marine live rock cannot survive in freshwater aquaria. Cheers, Neale.>
Freshwater sumps 11/28/2007 Hello again. You have been very helpful so far and I feel bad about pestering you for info but again there seems to be a lack of info on this subject. I am converting from marine to freshwater (most people go the other way) and have a sump which I want to use with this system. The tank is about 500ltrs with a 100 ltr sump. My question (to finally get to the point) is what would you recommend to put in the sump. Currently the first section is bio balls, then miracle mud with colerpera (sorry about the spelling) and finally live rock with a live sand bed. I know the live sand will 'die' and the live rock would be a waste. I was thinking about keeping the bio balls but replacing the mud with gravel and some sort of plants. The main section was to be changes to gravel. Have you any suggestions with what I am proposing. Any help gratefully received. Many thanks Paul. <Hello Paul. Unless you're keeping a hard water aquarium for, say, Tanganyikan cichlids then don't leave anything calcareous in the sump. For a standard community tank or similar, then opting for biological filter media of some type is probably the way forward. More bio-balls or some sponges would work well. Because nitrate control in freshwater systems is both easier (plants, water changes) than in marine tanks and less critical (freshwater fish largely nitrate-tolerant) there's no real need to provide denitrification in a freshwater tank. But some people have very effectively used 'vegetable filters' and 'algal scrubbers' as part of the filtration system, by placing fast-growing plants/algae into a brightly-illuminated chamber. There's a book called "Dynamic Aquaria" that discusses these, among other such esoteric topics. While hardly a book for the casual aquarist, it's an interesting read if your library has a copy. Basically the idea is that you optimise plant/algal growth, and then crop the plants (even daily!) effectively removing wastes in "solid form". Some freshwater plants, such as Cabomba and various floating plants, will grow incredibly rapidly if provided optimal conditions. I hope this helps, Neale.>
Marine to Freshwater. 11/14/07 Hello all. Quick note to great website as ever but am struggling to find my answer so hope you can help. I have run a largish marine set up (500ltr with 100ltr sump) for 2 years and am finding it difficult to find time for the maintenance. I am considering to go back to a fresh water set up but I want to use the existing equipment. Can you let me know if there are any pitfalls with this. <Essentially no problems at all. The main thing is that some systems used in marine tanks either won't work in freshwater or won't be helpful. Protein skimmers stop working below about SG 1.010, and things that drive off carbon dioxide (like trickle filters) won't be appreciated by plants (which want all the CO2 you can give them). Lime-rich materials used for decoration are fine in hard water tanks, e.g., with Mbuna, but can't be used in standard aquaria where neutral or acidic environments are desired.> The sump has miracle mud (though this will be got rid of), bio balls and live rock which is lit. What would you recommend to put in the sump? <Doesn't matter too much. Anything that will support biological filtration will be fine. So go by your budget or whatever appeals to you.> I have T5 lighting that alternates with a 'moon' light for the night time. Would this be ok or too much. <Depends on what sort of fish you are keeping. Some freshwater fish don't like bright light (e.g., Discus). But if you have lots of plants to provide shade, strong lighting is useful. Among other benefits, rapid plant growth suppresses algae and consumes nitrate. Floating plants like Ceratopteris are especially good for this.> I would replace the substrate from fine marine sand to normal gravel (or would you leave alone?). <Depends on the fish. Coral sand or lime-rich sand are fine for hard water tanks. But if you keeping a planted aquarium you need particular iron-rich, slightly dysaerobic substrates for them, and standard community fish wanting a neutral pH need an inert substrate such as silica sand or gravel. So research your stock list and planting ideas, and choose substrate based on that.> Any other problems I might encounter? <None that can't be prevented by research! On the whole, if you've mastered marine fishkeeping, freshwater fishkeeping should present too many problems. The common mistakes -- overstocking, overfeeding, inadequate filtration, etc. -- are identical. Live plants present peculiar problems similar to but different from those of corals. They need light, yes, but they also need CO2 and a nutrient-rich substrate (unless the plants kept are floating plants or epiphytes, in which case substrate is irrelevant). The range of invertebrates is more limited, primarily shrimps and snails, but by contrast with marine tanks, freshwater invertebrates tend to be easy to keep and prone to overpopulation if not watched (I have cherry shrimps breeding at a rate that would make me a billionaire if they were marine cleaner shrimps!). The main difference is really one of specialisation: while virtually all ornamental marine fish are from coral reefs, freshwater fish come from a range of habitats from mountain rapids to swamps to giant lakes to rainforest rivers. All require different sets of conditions. Much of the fun in freshwater fishkeeping comes from specialising in one particular habitat, and collecting fishes and plants typical of that habitat. You can then choose rocks, sand, bogwood and other decorative materials to create the "look" of that place, too. Water-worn boulders and Vallisneria would suggest a fast-flowing Asian river, while Anubias and bogwood roots could be use to create an African swamp. And so on. There are several books out there all about this aspect of the hobby. My favourite is 'The Complete Aquarium' by Peter Scott.> It the moment I have a 10 times water flow. Is that too much for fresh water, should I just use the return pump from the sump (3500ltrs p/h). <My freshwater tank has a similar turnover. It presents no problems to riverine fish that like water current, things like Corydoras, pufferfish, Plecs, midwater barbs and tetras, etc.> Many thanks for any pointers. Paul <I hope this helps, Neale>
Saltwater to Freshwater 5/18/07 Hi folks, great site! <Hello Billy.> I recently purchased a used 55 gallon saltwater tank that I want to use as a freshwater tank. It's your standard 55, 48x12.5x18 (or close, you get the idea). It has 2 Emperor 400 BioWheel Hobs and a Rena XP2 canister. I already removed the crushed coral. The plan is one or two Oscars (I know 55 is pushing it) and a pleco. <Sounds fine so far, though as you seem to realise, all these fish, if not actually huge, are messy, and tend to make small tanks with basic filtration rather murky.> This is the reason I was happy about the amount of filtration. In this area there is one person at one LFS that seems to know some things, and he's hard to catch. Other than that, you have your basic retail help. Very eager to help, just no experience. That's why I came to you guys. <Or better yet, invest in a good aquarium book. There are titles at every price point, and sitting down and reading is time well spent. Your public library will also have a variety if you don't want to buy a book.> I have a few questions about what to do next to convert the tank to freshwater: Will a good rinsing of the tank be sufficient? <Yes. Very few life forms of any kind, beneficial or otherwise, will survive going from marine to freshwater conditions (that's what makes brackish water animals so special). Almost all the bacteria, algae, potential pathogens, etc. will be killed merely by changing the salinity. Throw in a good clean with warm water and a sponge, and you're laughing.> It's actually soaking in the garage now to see if there are any leaks. <Good call.> What about the HOB filters, same? <Yes. Obviously you'll need to re-cycle the filter to get the bacteria back.> I've never used a canister. Is inside the stand, under the tank, ok? <Standard place to put it. BUT, because it is now working against gravity, pushing the water up from the filter into the tank, the pump moves less water. So knock off at least 25% from the stated turnover of the filter to allow for this and a certain amount of clogged filter media.> What if I lose power, will gravity pull the water out of the tank and onto the floor? <Not if you've connected it properly. Switching off the filter will simply stop the water moving. Nothing should leak out. A couple of tips though: Make sure there's a drip loop on the power cable, i.e., the lowest part of the cable between the filter and the power outlet is LOWER than the power outlet, so any dribbling water goes onto the floor not into your mains electrical supply. Secondly, if you're paranoid about leaking water, drill a small hole on the INLET tube in the aquarium an inch or two below the surface of the aquarium. What this will do is break the siphon if a leak develops in the canister filter system, so only the first one or two inches of water can escape from the tank. Any good aquarium book should show you these two tricks.> And same as before, will a thorough rinsing be adequate? What goes into the 2 baskets inside? Any words of wisdom for a nervous canister newbie? <Here's Neale's golden rules of canister filters.  Don't use carbon, zeolite, or peat. All three are unnecessary in most freshwater aquaria.  Choose a mix of mechanical filter media and biological filter media.  Filter wool is excellent for mechanical filtration but needs to be replaced periodically.  Good quality sponges or ceramic media are well worth buying because they last for many years.  Do a trial run setting up the canister filter with a bucket of water in the back garden or in a sink. The first time you use one you'll find them fiddly, so it's worth figuring out the rubber seals and various taps somewhere an accidental leak won't do any harm.  Once set up, leave the filter alone. You only need to clean it very occasionally, certainly no more often than once a month, and some aquarists get by cleaning them once a year. It'll be obvious when water flow is declining, and that's when to clean the filter.  If your filter is clogging up within weeks, it's overwhelmed. Either add a second filter, or be more proactive with the hosepipe and bucket, siphoning out detritus on a daily basis if required (this is what I do with my tank with an adult Panaque who could poop for Britain if it was an Olympic sport).  Never, ever clean the filter media in anything other than fish tank water.> My plan was to run the filters for a while in the sink to flush them out. <Seems a bit pointless but okay.> It didn't come with any actual inserts (media?), so those will be new anyway, but the tubes, impellers, and are where the filter inserts hang would get a good flushing. <Some filters come with media, some without. Hardly matters really some these are low cost, long lifespan purchases. A box of good quality filter media like Siporax will last ten years or more if looked after properly.> Thanks in advance for any and all help!!!! Billy <No problems. Good luck! Neale>
Marine to freshwater conversion 1/6/07 <<Hello, Jonathan. Tom here.>> I have a 90 gallon FOWLR with a DSB (4' of aragonite sand), 10 gallon refugium, 20 gallon sump, and a closed loop manifold that gives me about 18X circulation rate when I combine the sump return pump. <<Okay.>> I was always a freshwater keeper but last year built this marine setup and have found myself recently wanting to switch back to the freshwater world. How difficult would it be to switch this setup to freshwater? <<With a few changes, I don't see this as being a problem at all, Jonathan.>> I understand that the live rock, skimmer, and algae in the refugium would have to go with the fish, but what about the substrate? <<The aragonite sand would likely be one of the changes you'd have to make unless you intend to keep species requiring a high pH -- in the 8.0+ range, African Rift Lake Cichlids, perhaps. Because of the sand's constant release of carbonate into the water, you'll never get the pH down below what is commonly reserved for FOWLR and reef setups.>> I am interested in a planted tank. Could I pull the substrate and rinse it thoroughly? <<We're still at the issue of pH here, Jonathan. No amount of rinsing will change the sand's natural characteristics. Additionally, this rules out my earlier reference to the Rift Cichlids. Plants won't last a half hour.>> Is the 18X turnover rate too much for a planted setup? <<I would say so. You probably wouldn't want to exceed 12X with a planted tank and even this depends on what types of plants you want to keep.>> Could I find some beneficial use for the refugium? <<Depends on how closely you want to stick with the inherent use for a refugium. As you know, these are often used for inverts and delicate species that wouldn't survive in the display tank due to something trying to make lunch of them. Might take some imagination on your part but I wouldn't rule out the possibility of making use of it in a freshwater application. Obviously, since the display and refugium would have identical water parameters, your selections would have to be made accordingly.>> I am only testing the waters, y'all have always been very helpful before. Thanks for your advice. <<All in all, I don't see this as a bad way to go, Jonathan. It's been quite a while but I spoke with a fellow who laid out a large FW system almost identical to what I picture yours to be. Can't say I recall what his use for the refugium was, unfortunately, but equipment-wise, all he, understandably, lacked was a protein skimmer. All else was a 'saltwater' setup with the exception, of course, of the inhabitants and salt.>> Jonathan <<Good luck with the conversion. I'd be interested in finding out how you go with this. Tom>>