Alk Control

[Dustin813]

Hey guys I’m having some issues controlling the KH of my tank. Not only is it a bit higher than I want, there is some fluctuation in the level as well. It jumped from 10.5 on Saturday night to 11.5 tonight. Ca, Mg, No3 and PO4 all test well in the tank and are at optimal levels. I did a 10% water change today, but shouldn’t that have brought it down a little? At any rate, how do you guys control KH in your tanks?

 

[LobsterOfJustice]

Are you dosing in a regular schedule? Did you dose between the test on Saturday and today?

 

[Dustin813]

Are you dosing in a regular schedule? Did you dose between the test on Saturday and today?

I’ve never dozed Alk in the tank. It’s almost like the tank isn’t consuming it or something.

 

[Randy Holmes-Farley]

The water change might have raised alkalinity, depending on the alk of the new salt water, but not as much as you observed.

It may just be testing error. The tank may well not be consuming any alk at the moment, but it doesn't rise on its own.

If nitrate is falling, that can cause a small boost to alkalinity, as can many additives or top off water.

 

[Dustin813]

The water change might have raised alkalinity, depending on the alk of the new salt water, but not as much as you observed.

It may just be testing error. The tank may well not be consuming any alk at the moment, but it doesn't rise on its own.

If nitrate is falling, that can cause a small boost to alkalinity, as can many additives or top off water.

I dose the tank twice per week with Fuel and Eight.Four...could those be the cause of the Alk spike?

 

[Dennis Cartier]

Yep, Eight.Four is a buffer and it will raise alk. So you are dosing alk, just not realizing it. Buffers are not suggested to be used as you will run into problems like you are experiencing.

Dennis

 

[Dustin813]

Yep, Eight.Four is a buffer and it will raise alk. So you are dosing alk, just not realizing it. Buffers are not suggested to be used as you will run into problems like you are experiencing.

Dennis

Ahhh, thank you for clarifying that. I was under the impression that the 8.4 was simply to help in maintaining an optimal PH...that being said, what do I need to do to successfully maintain proper PH without the use of a buffer...without it, my tank likes to hang around 7.9-8.0.

 

[Dennis Cartier]

Ahhh, thank you for clarifying that. I was under the impression that the 8.4 was simply to help in maintaining an optimal PH...that being said, what do I need to do to successfully maintain proper PH without the use of a buffer...without it, my tank likes to hang around 7.9-8.0.

That is what the product is marketed for (maintaining a higher PH), however the effect is short lived, and it ultimately ends up as an alk boost.

For PH of 7.9-8.0, you don't have to do anything. PH only becomes a problem if it drops to 7.6. A common mantra is, "don't chase PH". So you are probably better off letting the tank stay at it's natural PH. If you would still like to look to raise it, search for threads about low PH. The common cause is too much CO2 in your indoor air. There are a few techniques that can be used in these situations (feeding your skimmer outdoor air, using a co2 scrubber, supplementing with kalkwasser, etc).

If your alk/calc requirements are not high enough to require supplementation, I would just let it run at its current PH.

Dennis

 

[Randy Holmes-Farley]

Ahhh, thank you for clarifying that. I was under the impression that the 8.4 was simply to help in maintaining an optimal PH...that being said, what do I need to do to successfully maintain proper PH without the use of a buffer...without it, my tank likes to hang around 7.9-8.0.

Not surprising since that's what Aquavitro used to claim about it, but their new description finally admits the obvious: it is nothing but a buffer that supplies alkalinity.