20 gal ADA AquaSoil tank w/excel, about 2wpg, no CO2

I have been using a weak version of EI for this tank. But no GH booster until recently. Was seeing slowing growth and a bit of algae. Figured to add the only thing missing from EI recommendations, GH booster. So I started.

GH=0 before, then
added 1/4 tsp Barr's GH booster
after adding GH booster GH still =0
waited 24hrs, then added additionl 1/4tsp GH booster
GH still = 0 after total 1/2 tsp addition

GH=0 from tap and GH=0 from tank
KH=48ppm from tank, and KH=88ppm from tap

GH reading consistent with either Lamotte, or AP test.
Using Lamotte: as above KH in tank = 48, KH from tap =88
AP test kit yielded ungodly high KH, but I stopped titrating because there was no color change with bounty of reagent drops added.

I began this simply wanting to round out my EI method, with addition of GH booster. But test outcomes do not allow me to know how much I should be adding. So two questions:

1) how much GH booster should I be adding in this tank

2) how are the GH & KH readings to be understood / do they make sense?

the lower KH in tank than tap may be understood because of depressive effects of ADA AS, but GH reading does not change with addition of GH booster, and I did not think it normal for KH to be wildly higher than GH.


Please to offer suggestions / thoughts.

cheers,
growitnow

It takes a tablespoon of GH booster in 20 gallons of water to raise the GH by 2 degrees. A quarter teaspoon would only raise it 1/12 th as much or about .17 degrees. You need to add a lot more.

KH measured by our KH kits is a measurement of alkalinity, which would be carbonates if the water contained only those anions in large quantities. Calcium carbonate is the usual substance in water that gives both GH (calcium) and KH (carbonates), so we usually see both KH and GH being high or low together. But, obviously, there can be other things in the water that contribute to alkalinity.

I think I am right about this. If not, I hope someone will correct it.

Vaughn, many thanks.

I believe EI recommendations are 1/4 tsp GH booster for 10-20 gal, and 1/2 tsp for 20-40 gal.

Since as my post I have just begun adding GH booster, is it common (and safe) to add so much more than EI guidelines? A tablespoon isn't even recommended for 125 gal. Not that you recommended that for my tank, but seems way overkill.

Just trying to figure out what I should be doing re: GH booster.