Alkalinity rising?

[DavidinGA]

One other general observation that might be helpful and is also really weird...

After I drop my Alk back down with lower Alk water changes and it climbs buck up on its own, it always stops at 10.2 and no longer climbs any further. Any idea why that might be a top-out point?

 

[Randy Holmes-Farley Verified Community Expert]

One other general observation that might be helpful and is also really weird...

After I drop my Alk back down with lower Alk water changes and it climbs buck up on its own, it always stops at 10.2 and no longer climbs any further. Any idea why that might be a top-out point?

Demand for alk (both biological and by precipitation of calcium carbonate on heaters and pumps) rises as alk rises, and so the negative feedback loop will keep alk from rising forever, even if it is rising at lower alk.

 

[Randy Holmes-Farley Verified Community Expert]

Hypothetical, how long could cement/artificial rock contribute to increase Alk?

The rock I have I bought used and it had been used for years prior (supposedly).

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Could be a long time. That might be contributing.

 

[Randy Holmes-Farley Verified Community Expert]

Just found this post and I'm having the exact issues expressed here. No matter what I do my Alk just keeps creeping back up.

Guess maybe I need to check for cement or fake rocks in my setup? I bought all my LR used, so who knows what's in there exactly...

Top off is what?

Any dosing of anything?

 

[DavidinGA]

Top off is what?

Any dosing of anything?

Top off is rodi tds 0,alk shows 0 (tested just to be sure).

Dosing absolutely nothing.

Feeding pellets and flakes.

Running an ATS, tiny bit of carbon and gfo.

System is less than 1 year old.

None of the rock looks like fake rock (none of that painted on purple rock that is supposed to look like it has coraline on it already). None of it looks like cement, but it all has coraline growing on it, so I'd have to tear into it all and pick some pieces up and basically discern by weight (any other method?)

 

[DavidinGA]

Testing Alk with salifert and it is giving appropriate readings from what i see. When I dose muriatic acid to newly saltwater, I've had new saltwater readings down around 5 Alk when I was working to drop tank alk levels (corresponding correctly with the amount of muriatic acid I dosed)

 

[Randy Holmes-Farley Verified Community Expert]

Probably just very low demand combined with some dissolution of sand and rock, which is normal but not usually seen against a higher background of demand.

 

[EricR]

...and making 1 dKH new salt water is relatively easy.

Old post but just want to make sure I read this correctly.

Is it OK to:
1. Mix enough Sodium Bisulfate into new saltwater to bring alkalinity (of new saltwater) all the way down to 1 dKH ?
2. Aerate the new saltwater overnight (or however long it takes) to get pH back up to reasonable level
3. Do VERY SMALL water changes using the 1 dKH saltwater -- seems like consensus is 0.5 dKH change would be OK all at once. (((I'd probably shoot for a bit less and space out the water changes by a few days to keep bringing tank dKH down)))

I'm fine with the math and saw your links but just verifying that 1 dKH water is acceptable with no adverse chemistry issues at that alkalinity.