High PH - 9.0

[rhschulz2000]

I have a 5,000 gallon oval pond that is filled with well water. Last year was my first year in "ponding", so I just tried some plants and goldfish. The fish and lilies did well, but the water hyacinth stayed yellow because of the high PH. So now I am ready to add koi, but I am concerned about the high PH. It seems to me that if I do a monthly water change, I am just fighting a losing battle trying to keep the PH down, when I keep adding well water.

Any ideas?

 

[addy1]

http://www.ponddoc.com/koihospital/Diagnostic/WaterProblems/pH.htm

see if this helps, we have low ph issues, our well is acidic.

And welcome to the group!

I put crushed oyster shells into our pond to stabilize the ph, they mention marble chips in the article they do the same thing.

 

[j.w]

rhshultz2000

I just put oyster shells in my pond for the first time and am hoping it works for me. I corrected my ph to about 7 and then the shells are supposed to keep it at that level

 

[vertigo72]

Is this a concrete pond? If so, did you let it cure or did you treat it with something ? With a PH of 9 I would stay away from koi until you find and fix the cause.

 

[vertigo72]

I just put oyster shells in my pond for the first time and am hoping it works for me. I corrected my ph to about 7 and then the shells are supposed to keep it at that level

Only if you start with more acid water (lower ph). Oyster shells, cat litter and the like all increase KH and PH. They do stabilise PH, but its not a cure for high PH.

 

[CometKeith]

Hi rhschulz, I agree with vertigo. Any cement product or limestone will make your water more alkaline. There is probably something near or in your pond that is releasing lime into it.

 

[rhschulz2000]

Thanks so much for the feedback. My pond has a rubber liner and while I did have a stone necklace cemented in this spring, I got the same 9.0 reading last year. I do believe that it is a reflection of the well water which has the same reading of 9.0. I assume I am going to have to use some chemical product (ph down) and then a bufffering agent to keep it there. I don't think I can afford to try and get it to 7.0, maybe would be ok at 8.0.

 

[addy1]

Well water can do that, but at least, unless you are filling it a lot, once you get it down it should stay lower. Once I got mine up and stable it has stayed up even with adding well water every day.

 

[vertigo72]

Thanks so much for the feedback. My pond has a rubber liner and while I did have a stone necklace cemented in this spring, I got the same 9.0 reading last year. I do believe that it is a reflection of the well water which has the same reading of 9.0. I assume I am going to have to use some chemical product (ph down) and then a bufffering agent to keep it there. I don't think I can afford to try and get it to 7.0, maybe would be ok at 8.0.

8 would be fine for koi. Getting your ph down might be easier than you think. It depends on the KH, that is your alkalinity, or PH buffering capacity. If it is low (and I suspect it is), your water will not have a lot of PH buffering capacity, and raising or lowering PH would be relatively easy. Once its where you want it, you could add KH+, clay, oyster shells and the like to lock it in.

I hear peat moss is an effective way to decrease your PH, but no idea how much or how best to use it.

 

[j.w]

Only if you start with more acid water (lower ph). Oyster shells, cat litter and the like all increase KH and PH. They do stabilise PH, but its not a cure for high PH.

Mine was acidic, then I got it up to 7 and added the shells to try and keep it up there in that range.

 

[rhschulz2000]

Well I should have done this first, but in checking my well water I found out it is near 7.0 PH so something else is causing me to go to 9.0. I have a rubber liner, I use matala mats for my mechanical filter and spring flo media for my biological filter. I do have 3 large clay flue liners that I set my marginal plants on. Could they be changing the PH that much.

 

[vertigo72]

test your KH. If your KH is zero, one drop of acid or something alkaline could cause huge ph swings.

 

[CometKeith]

Re the stone necklace that is cemented in. It's possible that your PH would have dropped this year because of plants that you added and the fact that PH can drop over time as the pond stabilizes, but the stone addition pushed up the PH again. Mine dropped after the first year from 8.7 to 7.3 and I didn't really do anything different.

 

[sissy]

You put the coping on your pond with cement it could be leeching into your pond and when I add water from my well I tried something new .I put a hole in a tote put filter media in the tote and then put my hose into the tote with an out flow from the tote into the pond .I have a fancy filter system my son installed in the house ,but think it was softening the water to much so I use the hose that comes straight from the well pump now and this helps catch anything just in case .Turn it on slow and let it go down through the filters and then out the bottom outlet .Since you have a bigger pond you could use a 55 gallon barrel to do the same