Cementacious construction inside biological ponds  9/7/05
Robert, Have sandy soil for my pond, have question  about  using mortar and flagstone on inside to make walls. Can the  mortar be toxic to fish.
<Is to a varying extent, depending on make-up>
I have heard of a plastic cement but can't find any  info .
Bill  Oglesby
<Use of plastic cement/s is advised. Are less caustic, toxic... still better to lower level of the basin/s while doing, curing this work. Bob Fenner>

New pond, owner 8/21/05
Dear "Crew":
<Jarvis>
           I just finished building a 220 gallon pond in my back yard, and is wanting to add koi ASAP, I'm not sure what to do though.
should I add any baking soda or salt?
if yes, how much should I add?
<... what for? I would test the water quality, at least pH, alkalinity and maybe add an inorganic acid to the water, or "wash" the sides down with a dilution of this... if the basins are new, cementacious... alkaline. Please read here: http://www.wetwebmedia.com/PondSubWebIndex/conclnrconstpd.htm
and: http://www.wetwebmedia.com/PondSubWebIndex/acidblchpds.htm>
should i but any water testing kits?
                                    <Yes, I would. : http://www.wetwebmedia.com/PondSubWebIndex/tstkitspds.htm
and the linked files above... Bob Fenner>>                                         
                     thanks: Jarvis

Pond construction... mainly 6/31/05
Just recently we added a cement pond to our back yard. And before putting water into the pond I need to know what measure should be taken to prevent leakage.
<...?>
A few question I have is how long should I allow the cement to cure before cleaning it with a solution? And what type of solution should I use?
Thanks for your help!
Diamondmind
<The basin/s shouldn't leak if they've been constructed properly... some folks seal concrete with a coating that aids in protecting the material and rendering it less likely to affect water chemistry. Most installers use an acid wash to reduce alkalinity... some people just utilize vinegar here, but professionals often dilute Muriatic (3M HCl) and brush this on, rinse, pump out... These issues are covered on WWM: http://www.wetwebmedia.com/PondSubWebIndex/Pond%20Sub%20Web.htm
You might avoid a good number of future issues by studying now... Bob Fenner>

Pond Construction Sat, 2 Apr 2005
Greeting,
I have been reading several of your excellent articles on the web.  I am looking for specifications for a pond with a concrete (or gunite) topping over a liner.
<Specifications? Your installer (I strongly suggest "going Union" here) will know what these are... depending on depth, slope... if you're going to "plaster coat" the gunite (I would with something)...>
I also need an installer for a client in the Palm Springs (Indian Wells) area of Southern California.
<Mmm, I'd consult the "Yellow Pages" under "Swimming Pool Construction"... get at least three bids, talk with whoever they give you references for their recent work>
I would appreciate any direction or references that you might have.
<Unfortunately it's been many years since doing actual jobs in your area... but there are likely still a few excellent companies out your way... There are MANY pools and water features out that way as you no doubt are aware. Bob Fenner>
Rick English English Pool Consulting 

Waterfalls and mortar
Bob,
I am building a waterfall for my fish pond and would like to use mortar to set my rocks onto the liner so the water will go over the rocks instead of under them.  I am concerned about the mortar leaching out into the pond.  Is there anything I can do to the mortar to prevent this?  I've tried the black biofalls foam and found it very difficult to work with.
Thanks,
Gail
<Yes. Make sure and use "plastic cement" in your mortar mix... much less alkaline than "plain" Portland cements... Mortars are just cement, sharp sand, water and possibly a coloring agent... and easier on your skin in working with it as well. Bob Fenner>

Pool slide
I have just shotcreted my pool and in ground slide.  Do I need to browncoat the unleveled areas and rough spots before Thorosealing the slide or will Thoroseal fill in all these voids?
<Not unless the current surface is very rough>
  Will Thoroseal provide me a smooth sliding surface;
<Not enough to likely suit you>
if so, how do I achieve this.  Do I trowel it on or use a paint roller or brush?  That you for your response.
<Look into smooth mortar "plaster coating"... can be done by oneself... but if this job is very big (like a swimming pool), better to have professional "pool plasterers" trowel it out. Bob Fenner>

Acid wash acid for ponds
Hi I just read your article on Thoroseal I just used it to reline my koi pond you mentioned a light acid wash before introducing live stock What product can i buy to do that. Thank-you for your time Danny Fitzgerald
<Hydrochloric, as three molar concentrations sold as Muriatic Acid is your best bet here. Sold in swimming pool supply shops, concrete et al. businesses. Please read here re doing such acid washes: http://www.wetwebmedia.com/PondSubWebIndex/acidblchpds.htm
and follow carefully the cautionary remarks. Bob Fenner>

building concrete pond???
Robert,
<Jim>
I am constructing a pond with the inside dimensions of 6 x 10 by 3 deep.
I am planning 6" wall and floor thickness. It will have a 3" bottom drain line and a set in concrete wall skimmer, like a pool. 
<Do make the "casting" around this skimmer assembly a good six inches thick all the way around as well>
The walls (sides) are vertical 90°. I have a few questions and am hoping your experience will shed some light on them.
<I'll try>
1. I am using a 6-1/2 bag mix with ipanex admix for waterproofing and will plaster the inside with black plaster, is a liner still needed.?
<Not needed... but good/worthwhile insurance... especially in areas where the ground moves (earthquakes, freezing...)>
2. I am tying rebar and will hang the inside wall forms as one 4 sided piece (suspended 6" above the floor.
<Make this 3" on your stand-offs... cast in about the middle>
Can I pour this all at once, floor first then walls....or will it try to seek it's own level. also do I need a vibrator wand for the walls (trapped air).?
<Best to pour all at once... the floor first... how are you forming up the walls? If they are vertical... are they being molded somehow?>
3. If the slump is low enough can I just pump the walls starting at the bottom and building then vertical. or will it all sink without a form.
?? I hope this will work.
<Not exactly... even with an absolute lowest slump the mix will compact, compress>
3. Don't I need a hydro-static valve in the bottom drain to protect against the pond raising out of ground when emptied for maintenance.?????
<Yes! Or other provision...>
I would love to use gunite except the job is too small.
<Mmm, not necessarily too small... Have you checked with the pool sub's in your area? Do take a read through the "Pond Index": http://www.wetwebmedia.com/PondSubWebIndex/Pond%20Sub%20Web.htm re construction methods on our sites before actually initiating construction. I encourage you to go with an underlying liner, and for us to chat re the forming of the walls, bottom of the system. If your design calls for vertical walls, either reconcile yourself to making them of block or forming them with plywood and snap-offs... Let's keep chatting if I'm not being clear. Bob Fenner>
thanks
Jim brown

Re: building concrete pond???
bob,
thanks for the assist. a ready mix co. quoted $370 for the concrete and $170-$200 for the pump... 
<Mmm, about right>
check this ! today got 2 replies from gunite guys, one at $1,600 and one at $1,900. think I will stick to working out the pour version.
<... the difference isn't as much as you might think here... the pour option includes having to hand-pack, move around... even with the pumper, about seven yards of concrete... at about 2 1/2 tons a yard... yes, about 35,000 pounds of material... so, you'll need a few friends, for a few hours... the gunite folks will probably finish the shooting, leaving you with only cement plaster coating to do... something (my back's starting to ache) to think about>
I think your right about the liner. I will sketch my idea of the form for the pour and .PDF it to you early next week. got a lot of rebar to do this weekend.
<Real good... the progress will be well worth it... and give you a much better idea of what you're up against. Bob Fenner>
have a good one.
Jim