I've seen comments about using Please Release Me and other treatments to keep fish healthy. Sea salt is recommended by some folks.

So here's my question: My normally acidic pond now has a pH of 7.8 (I don't know how). However, alkalinity and hardness are down to the 20s, half their usual. My guess is that this is a result of excess rain. I'd like to restore the minerals, but don't know if adding lime would be smart with an already high pH.

Any comments? Would sea salt have any [positive effect? I do have a decent bloom, maybe 30 inch viz, due to a total of 85 lb fertilization, and the fish seem to be doing well.

That's why I've been searching the archives for anything pertaining to salt. I've only heard of one instance (not thru the forum) where rock salt was recommended to be added to a large BOW.

Gypsum is supposed to increase Hardness without affecting PH. All this rain has raised my PH into the mid 8s. I was going to do an Aglime/Gypsum addition this weekend, but if adding more Aglime is going to push it higher, I may hold off on adding any more.

I believe Clay n Pray just dumped a slurry of Gypsum into his pond without any affect to PH. My Alk is very low as well (around 60), and my Hardness has always been immeasurable.

The Ag Extension down here told me pieces of sheetrock would work (which I experimented with in small quantities) but it's got other stuff in it that may not be beneficial, so I gave up on it.

I've considered dumping a small quantity of rock salt, but I'm holding off until I can get more info, preferably from someone with experience.

I recall reading that there is a upper limit on PH that cannot be physically surpassed using Aglime.
I just searched but did not find it.
Google might pull it up.
Gotta get ready for work now, no time.

Calcium Chloride--I've used it several times in RAS and saltwater systems when raising corals,inverts, and fish with a high calcium need. I wouldn't be worried about raising the pH at 7.8 (depending of course on what time of day it was tested, just before sunrise is the most critical time to test). Ag lime won't push the pH above 8.5 or so, which I would be fine with. I typically shoot for alkalinity around 100-150 mg/L and calcium at around 100 mg/L.

Possible---Yes

Affordable---No

I believe you can add more agg lime and that will increase the waters hardness and calcium. Don't worry so much about the pH increase because it wont get much higher than it already is. Concentrate on increasing the alkalinity using the agg lime. You can also get some Gypsum from Todd Overton, spread it along your shoreline, where wave action will help to dissolve it. It will increase waters hardness and calcium. I remember Al (Fireishot) put his gyp on a tarp near the shoreline and then used a trash pump to wash it into the water. I would expect some of it to dissolve during this process and would spread it along the waters edge. You could add agg lime the same way.

I, for one appreciate all the input to Anthropic's post. Reading thru everyone's responses has risen a few questions...

1st-why is it more important to test PH before sunrise, as opposed to mid day? I would think you'd want to know when PH was at it's highest, not its lowest. If it's topping out at 8.5 midday, what are the chances it'll drop below 6.5 over night?

2nd-if I understand correctly, if my PH is topping out at 8.5 currently, adding more Aglime isnt going to push it any higher, just help buffer the swings to make them less drastic. Correct?

3rd-what's the distribution rate for Gypsum? Aglime is about 1 ton per surface acre. Is Gypsum the same?

Finally-how do you test for calcium? I've never seen a tester that measures calcium.

Pardon my hijack Anthropic. Seems we're running parallel concerns.

Agricultural limestone can be used
to increase calcium concentrations
(and carbonate-bicarbonate alkalinity)
in areas with acid waters or
soils. However, at a pH of 8.3 or
greater, agricultural limestone will
not dissolve. Agricultural gypsum
(calcium sulfate) or food grade calcium
chloride could be used to
raise calcium levels in soft, alkaline
waters.

Thanks to Mike, Eric, Tracy, Acoursey, and ClaynPray for your input. Guess I'll take another sample in a couple of weeks of more normal weather & waterflow to see how things look before taking action. Really shocked at pH reading after all the acidic rain!