Soft water question

[planted120]

I just changed cities and the new water here is way different than the water I'm used to. I will tell you what I am up against.
ph 6.8 from the tap-- goes to 7 overnight
kh less than 1
gh less than 1
no detectable iron or phosphate
the plant are showing serious deficiencies but I don't know of what.
I have added k2so4 and mgso4, also sodium bicarbonate and trace to get
ph 7.1
kh 3
gh 3
and .1ppm iron(chelated)
due to fish waste I have .5ppm no3
plants still have white viens and curled leves, also almost no growth.
I have 120 gallon 24"deepp tank with 320 watts of t8 lights and good reflectors.
no co2 at this time, I am scared of crashing the ph in this low kh water.
I do have a pressurized system with a needle valve, no controller.
Is this all lack of co2 related or am I missing somthing else?
no algea either.
thanks, looking forward to hearing from somone with water like this.

PS: the discus love this water.

[Wasserpest]

Seems like you are doing the right things... and CO2 is the bottle neck.
Is your NO3 really 0.5 ppm, or do you mean 5 ppm? Most test kits can't distinguish anything lower than 2.5 ppm.
If PO4 is at 0, you might want to get it up to around 0.5 ppm, zero PO4 could contribute to the problems you mentioned (starving plants).

[Nordic]

Also with kH3 and pH7.1 your CO2 system is not working optimaly, as the CO2 levels are under 9ppm.

Dunno how the other stuff you added inlfuenced this though.

[planted120]

sorry,, no3 is 5ppm and .5ish po4(seachem kit)
co2 is not running at all right now

[Nordic]

stupid me...

[Rex Grigg]

planted120,

Where do you live? Your water sounds just like my water.

[planted120]

Vancouver BC, Canada.
What do you add to yours, any tricks? Please tell.

[Rex Grigg]

I add calcium carbonate which will raise kH and gH. Two tablespoons will raise each 4 degrees in 50 liters of water. I add epsom salts for the magnesium. I also add a bit of baking soda.

Go to http://users.frii.com/gbooth/AquaticConcepts/ and read the Tech Brief on Water Chemistry. It will help you out a ton.

[Nordic]

Hi Rex, how much epsom /volume of water, how do you dose?

I suspect we may have low levels (doctor gives me magnesium tablets to stop leggcramps, said I have deficiency, probably from water i guess)

[Rex Grigg]

I like to get the magnesium levels in the 5-10 ppm range. Go to http://www.csd.net/~cgadd/aqua/articles.htm and either use the on-line calculator or better yet download the new calculator and use it to find out how much of most nutrients to add.