Got my new 50G tank filled and the filters running a couple of days ago ... expecting my plants to arrive tomorrow morning.

Today, I tested the GH and KH of my water and found the following (with an inexpensive test kit, so I am not going to base my decisions entirely on it):

GH: 11 - 12 and KH: 1 - 2

Another aquarist in the area told me that our GH was really high, so I was expecting that. But, the water beginning to turn yellow after one drop of the KH test solution surprised me.

Also, I ran my brand new DIY external CO2 reactor (Tom's design) all afternoon with a CO2 drop checker in the tank to see how it would do. I was fun to watch it in action -- I know, I need to get a life -- and the drop checker turned green enough, as far as I could tell. My tank water was really absorbing the CO2 -- the bubble at the top of the reactor (if there even was one) never got near the venturi loop air tube. There was always just a few bubbles playing around where they were visible. Anyway, I was very pleased that it seemed to work so well. Thanks, Tom.

My questions:

1) I assume that I should NOT add SeaChem Equilibrium to my water at water changes (I am going to use the Estimative Index method), since it is already rather hard. Or, does Equilibrium do something else that is needed?

2) Should I do anything to increase my KH, even though the plants do not mind low KH? I read where Tom Barr said that CO2 measurements can be tricky with very low KHs. Is there a simple way to raise KH? SeaChem also sells "Alkaline Buffer" that is supposed to raise KH, I believe. However, as I created 1 liter of 200dKH water today by adding 6g of baking soda (sodium bicarbonate) to it, it would seem that I could easily raise my tank's dKH by about 2 by adding 12g of baking soda (rough calculations) to the water -- assuming sodium bicarbonate is safe for fish. Sound like a good idea?

3) The bubble counter on my Milwaukee CO2 system is not super consistent and occasionally slows down or speeds up -- maybe from 2 to 3 bubbles per second or from 3 to 2, that sort of thing. If I had to guess, it seems that significant changes in my room temperature seem to effect the bubble rate. Does that sound right? Or, might there be another problem? I am trying to use the needle valve as little as possible ... I may have been over-using it.

Thank you for any advice you can give.

Looking forward to planting my very first tank tomorrow. Thanks to Tom and all of the others who help to keep this site going strong. I learned in a few weeks what would have taken probably years otherwise. And, don't even get me going on the the EI system -- simple, effective -- it's really quite amazing.

Hi,
I don't think there's any need to use Equilibrium, at least that I'm aware of. I just use epsom salts and calcium chloride to raise my GH, since it's 0. At 11 or 12 there's no need.

Measuring CO2 is not an issue with low KH if you are using 4KH solution in your drop checker. Your tank water has nothing to do with that.

I used to add baking soda since my KH is 0 from the tap, but I gave up after people told me that there was no need. Fish and plants seem healthy and fine. Adding KH can cause fast pH changes especially when you're starting off at low levels, therefore I think it's actually more beneficial to the fish not to add it since it's very difficult to keep it stable when doing weekly 50% water changes. The only issue would be on a tank that you're not changing much water on regularly, the pH will tend to drop due to the excessive acidic compounds building up in the water and a lack of a buffer. If you're doing EI that's probably not going to be an issue.

Keep in mind that your co2 will probably have to be turned up after you add plants and they start growing, after all, nothing is using it up right now. I can't comment on the issue with the bubble counter since I don't use one.... but I would say that as long as your drop checker is green I wouldn't worry about any apparent variation.

Thanks, Carissa ... this was very helpful.