Aquatic Gardens Ponds, Streams, Waterfalls & Fountains: Volume 1. Design & Construction Volume 2. Maintenance, Stocking, Examples V. 1 Print and eBook on Amazon V. 2 Print and eBook on Amazon   by Robert (Bob) Fenner

Problem with Bleach   9/28/10
I have a 3500 liter fish pond that was drained of all the water, and bleach was put in to the remaining dregs of water to prevent mossies from hatching, I now want to reintroduce fish into the pond. I have filled and emptied the pond three times and added a dechlorinator. How do I get rid of the bleach from the water and get it ready for fish.
<Go to the chemist, or photography shop and buy solid sodium Thiosulfate (hyposulfite)... apply a few pounds of this (mix in water and pour along the pond edge... and check for free chlorine an hour or more later... Add more hypo if you're still registering free chlorine. Bob Fenner>
Re: Problem with Bleach   9/29/10
Thanks will try this
<This is the best, most-assured, least expensive and non-toxic means of neutralizing sodium hypochlorite (bleach). B>

Curing a pond.   2/26/10
dear Sirs,
I have built a brick form pond that has been cement rendered. Sealant was applied to the walls it was built against and then to the brickwork, but not to the cement render on the inside of the pond. I have tried many ways to
reach a suitable ph level . I have filled the pond, cleaned the sides and base with vinegar solution and have added both vinegar and mild (30%) hydro choric acid to the water. I have left it for a week or more and repeated the process. However, as soon as I drain and change the water the ph shoots up. The water source is a neutral 7.It is now over a month.
Any advice please
Anthony Sullivan.
PS I live in Malaysia
<Hello Anthony... how "high" is your pH now? If below 8.0, I would not be overly concerned... As you have already used vinegar/Acetic and HCl acids for washes, I don't think that more exposure will help much here, and
perhaps may lead to weakening of the cement (Next time less alkaline material). It is likely prudent/best to just leave the water in the system, try growing some easy plants (floating or emersed) for a few months, and you'll likely see a gradual lowering of pH here. Bob Fenner> 

Does algaecide and chlorine cause damage to pond liner?  9/6/09
Hi, I'm a new pond enthusiast and have successfully put new life in our pond that was falling apart. We don't have and may be won't have fish and are still in the process of deciding which water plants to keep. In the
mean time, I've been using algaecide in which the active ingredient (60%) is
Poly[oxyethylene(dimethyliminio)ethylene (dimethyliminio)ethylene dichloride. FYI... I use this same algaecide for my swimming pool.
<Yes>
I really want to know if this type of algaecide will damage the pond liner (45 mil rubber liner).
<Not as far as I'm aware. Butyl/Rubber liners are quite chemically unreactive... and any material "lying" on the liner could be easily rinsed, washed off>
I have also been putting chlorine in my pond. This is same stuff that I've using for my swimming pool. Does that damage the pond liner?
<This might... hypochlorite is a strong oxidizer... I would take care not to use too much (less than 1 ppm free Cl), nor use in water with a low pH (under 6.0)>
Thanks in advance.
- Hiren
<Welcome. Bob Fenner>

High pH in concrete pond  - 04/05/2006 I built a cement pond with cement from Home Depot. I sealed it with Thoroseal and had problems with the pH being 8.4. My pond shop suggested that I add vinegar for a couple of months so I did that and washed the pond out. The pH is still too high. The local cement dealer looked up Thoroseal information and suggested putting a 12% solution of salt in for one day. <Mmm, salt won't help...> This required 120 lbs salt but this did not work either. Do you have any suggestions? <Yes... You could try a good/strength acid wash: http://wetwebmedia.com/PondSubWebIndex/acidblchpds.htm and the linked files at top> Can I paint a rubber or neoprene paint on top of the Thoroseal? <You can/could> If not, how do I get the Thoroseal off? It actually seems like the second coat of Thoroseal has come off on its own as it was a slightly different color from the first and I can see that hardly any of it remains. George Strang <Can be chipped and acid-washed/etched away. Do pay close attention to the cautions/warning statements re this procedure. Might I ask what your intended use of this basin/pond is? It may well be that you'd be better off allowing "biological intervention" here to cure the high pH/alkalinity issue. Bob Fenner>

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>

Vegetable Oil... In a Pond? Here's one for ya, <Ho boy> My step-son, in an attempt to prime a non-submersible pump went and poured a half of a bottle of vegetable oil in the hose per the manufacturer's instructions, <What the?> which is now in the pond. It's @ 500 gallon, 4" deep. I tried to skim off what I could with a pool skimmer net (which is now like paste) but it has coagulated into white clumps which is now on the bottom and covering the liner. Is there anyway short of draining and scrubbing with Dawn to get this out? Such as a natural biodegradable neutralizer or an  aggressively large cooking oil eating fish? James <Thank goodness you have a sense of humor. For this size system, I would drain all (including plumbing, filter...) and use a detergent as you mention. Do take a read through our Pond subweb re plumbing, check-valves... arrange for this conduit to stay primed when the pump is off, out... and no more vegetable oil!

Aquatic Gardens Ponds, Streams, Waterfalls & Fountains: Volume 1. Design & Construction Volume 2. Maintenance, Stocking, Examples V. 1 Print and eBook on Amazon V. 2 Print and eBook on Amazon   by Robert (Bob) Fenner