Barr's GH Booster: Yikes! should/can I actually add 5 TBSP GH booster?

[growitnow]

Hello,

I just got my water quality report. "Total Hardness" is 2.42 mg/l and so my tap GH is 2.42 ppm, which essentially is 0.13 degrees GH (2.42ppm/17.9ppm)

In order to bring GH up to even 2 degrees, this means I would have to add about 5 TBSP Barr's GH booster for my 90gal. Can this be correct and should I do it? It just seems so much.

estimate:
1 TBSP GH booster will raise GH in 20 gal by 2 degrees. So approximating for my 90gal, 5 TBSP will raise GH by 2 degrees in 90-100gal. That's a bloody lot of powder. Does anyone else add this much?

 

[Tom Barr]

I think 2 tsp is enough once a week after water changes.
Remember that a lot of the GH booster is hydrated, * 7H2O, *2 H2O etc........SO4's etc........little is the rawstuff.

You might do 4 tsp total per week.

So 5 is not too far off.

Regards,
Tom Barr

 

[growitnow]

Hello Tom, thank you. I will follow the recommendation to add 4 teaspoons each week in my 90gal tank.

But I do not understand the logic and I would like to. I did mean 5 TABLESPOONS (TBSP) above, as seeming too much, not 5 teaspoons (tsp). My tap has 0 GH.

Let's say I want to get my GH from zero up to 2 degrees GH.

What I think I know:
2 TABLESPOONS of GH booster will raise GH in a 20 gal by 2 degrees GH. Thus, 5 tablespoons of GH booster will raise the GH in a 100gal (90gal is my tank) by 2 degrees GH. If I want to end up with 2 degrees GH, I need to add 5 TABLESPOONS GH Booster (not 5 teaspoons).

Logical conflict - why I am confused:
There are 3 teaspoons in 1 tablespoon. Five tablespoons = 15 teaspoons to get the GH from zero to 2 degrees.
Four teaspoons (in your reply above) = 4 teaspoons recommended / 15 teaspoons needed = .27
.27 x 2 degrees GH = .54 degrees GH
If I add 4 teaspoons of GH booster my GH will change from zero to .54 degrees GH
.54 degrees GH is still too low

Either .54 degrees total GH is adequate, or my logic is wrong. What is wrong with my logic?

I have been searcing other posts to figure this out but I cannot.
http://www.barrreport.com/showthread.php/6861-GH-Booster?highlight=how+much+GH+booster