pool plaster ponds

[donovan]

Hi all
I am in the processs of building my own pond.With the construction I have used the exact same mix as you would for a swimming pool.First I put down 100mm steel reinforcement.Then I bought in ready mix pool mix.I let this dry for 5 days.3 I put on hand packed plaster +- 5cm thick after which I made the surface rough.4 Now I am going to finish with charcoal marble plaster.

The question that I would like to post is what to treat the marble plaster with as it is going to leach chemicals into the pond that will take the PH to very high levals.I have heard that you must was the plaster with vinigar.
or fill the pond up with water add pool acid and take your PH down to 6.5 let the water stand for 5 days then drain wash and brush the walls and fill the pond again ..
Aloe pools & ponds

[MikeM]

Donovan: Welcome!

Both of the techniques you mention have been used successfully. The swimming pool industry uses muriatic acid a good deal, but as DickB mentioned elsewhere on this Board, it can be dangerous to handle compared to vinegar ... which is pretty cheap if you get it by the case of gallon bottles at a warehouse store. If you use the "fill the pond with acidic water" approach, test the pH regularly and keep adding acid as the pH increases to keep it low. You can use both together: scrub down the walls with vinegar. Rinse. Do it again. Rinse again. Then fill pond with acidic water, adding additional acid as required over the course of a week or two. Drain. Then I've seen some say they washed again with vinegar to try to neutralize even more thoroughly.

Be aware, however, that you may go a long time before a new concrete pond has no impact on pH. It can be years. But, the degree of the impact can be reduced considerably. The goal is to avoid extremes and to avoid fluctuations every time a water change occurs. [See thread re: using phosphoric acid below.]

Hope to hear how things turn out for you.

[donovan]

Hi Mike

Thanks for the speedy reply.I will keep you updated with the results.Other than the PH reading will there be any other reading that will be on interest.

Donovan

[MikeM]

Are you kidding? There are folks who lurk on koi boards who salivate over water parameters. If you found a way to test for levels of dissolved boron, somebody would want to discuss optimal levels and the best dosing techniques. :lol:

I have to admit that in your shoes I'd be focused on the pH and not worry about other testing until it was down to an acceptable level. But, you might find it interesting what the KH and total hardness do comparing your source water to the initial fill, then again 12 hours later and at the end of the treatment. (And however times in-between you care to do it.)

I want a concrete pond. Maybe in a year? ... if the cement shortage clears up by then? I'm thinking about it.

Good luck!