Struggling to Raise KH & GH

[thisguy77724]

For about the last month or so I’ve been struggling to get my KH & GH to my target values of 4 and 6. I use Shrimp Minerals KH/gh plus and SL Aqua more KH. Usually my GH will raise ok but I really have to dump in a lot of either product to raise my KH. What could be causing this?

A little about my tank:
-105 gallon tank
-oase biomaster 600
-running c02 injection through an inline reactor controlled by a Milwaukee ph controller set to 6.7ph
-I fertilize with easy green 1-2 times a week, I also add easy potassium 1-2 a week as well
-50% water changes about every 2-3 weeks
-temp set to 72
-inline UV sterilizer

 

[Koan]

What is your substrate? If it's aquasoil, how long was it installed?

Depending on the brand, fresh aquasoil can soak up your KH for quite a while.

This is what I use to remineralize my makeup water for KH :

Potassium Carbonate [K2CO3] 99% ACS Grade Powder 500Gm Brand: Dawn Scientific Inc. - Walmart.com

Buy Potassium Carbonate [K2CO3] 99% ACS Grade Powder 500Gm Brand: Dawn Scientific Inc. at Walmart.com

www.walmart.com

For this granular form, a shy 1/4 teaspoon will raise 10 gallons by 1° KH .

(If you're keeping shrimp or snails, it's important to use an ACS grade potassium carbonate source, because food grade can have copper contaminants.)

I use NilocG Shrimp GH+ to remineralize for GH, or you can use dry calcium sulfate and magnesium sulfate using this dry salts fertilization calculator

 

[Naturescapes_Rocco]

Do you use aquasoil, or inert substrate? Is there any reason you want 4KH? 6GH is a good target.

Many plants do best at 2-4KH or lower. If you have aquasoil-based tanks, there's really no reason to raise KH, just curious why you want that target.

 

[MrJG]

If you’ve bought shrimpy minerals from Amazon be aware that there is a company selling fake product. Double check the packaging, fake stuff clearly has an American flag in the label.

 

[thisguy77724]

What is your substrate? If it's aquasoil, how long was it installed?

Depending on the brand, fresh aquasoil can soak up your KH for quite a while.

This is what I use to remineralize my makeup water for KH :

Potassium Carbonate [K2CO3] 99% ACS Grade Powder 500Gm Brand: Dawn Scientific Inc. - Walmart.com

Buy Potassium Carbonate [K2CO3] 99% ACS Grade Powder 500Gm Brand: Dawn Scientific Inc. at Walmart.com

www.walmart.com

For this granular form, a shy 1/4 teaspoon will raise 10 gallons by 1° KH .

(If you're keeping shrimp or snails, it's important to use an ACS grade potassium carbonate source, because food grade can have copper contaminants.)

I use NilocG Shrimp GH+ to remineralize for GH, or you can use dry calcium sulfate and magnesium sulfate using this dry salts fertilization calculator

My substrate is aquatic soil capped of with pretty fine sand. Tank is about 5 months old since I rescaped it but am using the same filter and filter media.

 

[Koan]

What brand of aquasoil, do you remember? 105 gallon tank worth of aquasoil is a lot of volume.

5 months is not very old, was the aquasoil new at the time of rescape? Or reused? If it's new I'm not at all surprised if it is continuing to hoover your KH down All you can do is keep testing and keep topping up the KH until it stops dropping

 

[thisguy77724]

What brand of aquasoil, do you remember? 105 gallon tank worth of aquasoil is a lot of volume.

5 months is not very old, was the aquasoil new at the time of rescape? Or reused? If it's new I'm not at all surprised if it is continuing to hoover your KH down All you can do is keep testing and keep topping up the KH until it stops dropping

Sorry I meant literal aquatic soil like used in ponds, not the little balls of aquasoil specifically made for aquascaping.

 

[Koan]

Okay well the action is the same. When we say that aquasoil soaks up kh, what that means is that the acids given off by aquasoil interact with the carbonate and bicarbonate ions in your water, producing carbon dioxide and water. The acid reaction literally breaks down your carbonate ions.

This is the same reaction that happens in your test tube when you do a KH test, just on a smaller scale because the organic acids in your soil are much weaker then the acid used in the test:



This is the engine that drives low-tech tanks: acids in the soil react with carbonate in the water to create small amounts of CO2 for the plants

In the case of pond soil, humic acids from organic material, usually peat, in that soil are doing the same thing. So yes, it's literally eating up your carbonates , so you have to continue to add them in until that acid capacity is used up.

If there's enough humic material in the soil, which is likely, this may be a permanent part of your water change maintenance. The amount of humic material in commercial aquasoils is much lower, so over time this problem decreases if you're using aquasoil.