What would you do with this water?

[Tom Wood]

We recently moved west about an inch on the attached map. From the red zone to the green zone. After failing with my usual routine, everything almost died, I got wiser about my new water. It's 24 dGH and 16 dKH per testing, and per the technical water report:

83 mg/L Calcium
50 mg/L Magnesium

And, not a part of GH I know:

21 mg/L Sodium - Is this bad?

So that's a 1.7:1 ratio of Ca:Mg. I'm presently reconstituting 100% RO water from scratch but I'd like to use some tapwater in the process, I think. To get a better ratio I'd have to ADD Ca to what is already a hard water problem.

I tried the Barr GH Builder/Booster with 100% RO and hygrophila difformis stalled completely. That big gob of potassium is suspect, but I can't prove it. Since I depend on h. difformis for nitrate control with goldfish, I'm looking for a sure deal in terms of plant growth.

Tank is 90 gallon, 3WPG, CO2 injected with all the ferts.

Thanks,

TW

 

[Spar]

Re: What would you do with this water?

That looks rough! My tap water is near RO water as is, so my fish would go into culture shock if they had those changes.

You would still have a fairly high GH and KH, but personally I would just do a 50/50 Tap/RO mix and leave it at that. You will still have more than enough Calcium and Mg left in the end. And not have to bother with adding extra products.

It is tough though on a 90g tank as you will be having to hold ~25g's of RO water between water changes somewhere. I have a 180g tank that I do 60% water changes on, so I used to have to fill a bucket up with 40g's+ of RO water 2x per week (semi-weekly water changes).

Here is my old system of water changes with RO/Tap mixed:
http://www.fwstingrays.com/ro_water_discussion.htm

I now just do 100% tap water, but the above worked quite well.

 

[Tom Wood]

Re: What would you do with this water?

Yeah, I tried a mixture of tap/RO and the plants did not respond well to that either. I think it's the Ca:Mg ratio, which would still be wrong even with a mix.

I bought a 44 gallon heavy duty plastic trash container and use that to collect the RO water in. Filled it 5 gallons at a time and marked it at 35 gallons, then calculated the number of gallons drained from the aquarium per inch, and marked the tank at 35 gallons down. (Actual water volume is about 70-75 gallons) After all was done, I had about a half gallon left over in the trash container, so close enough.

Since it looks like I'm stuck with this, I'm looking for ways to minimize water changes, which means I need to get rid of nitrates better. I just ordered some duckweed and water hyacinth that I'll add to the sump.

TW