Challenging Water Change With Well Water

Lou Ahlquist

New Member
Oct 7, 2018
Central NJ
I have a 250 gallon tank soon to come online.
One of the sticking points currently is how to do a 125 gallon water change (50%) with well water that is too soft, needs to be heated and has a pH of 5.8 out of the ground (untreated) that needs to be aerated first. Once aerated the water comes up to pH of 7.7.
I cannot run it through the water heater because the heater is full of (treated) water that has already gone through the water softener and calcite bed. Thus, the water now has too much sodium/ or out of calcite bed alone has a dkH of 14.

Apparently I need to heat, aerate to correct pH and adjust Mg, Ca and kH levels of the well water: Ca= 15ppm, Mg= 1.74, KH= 2dkH, GH=2~3 dH, , NO3=1.5ppm.

**The water softener was installed to correct supposedly high Fe levels that I cannot read currently. Reading of raw well water is 0.0 using Seachem multitest kit.

The only solution I have come up with is to get a 125 gallon water tank then: heat, aerate and adjust the Ca, Mg and KH levels in it then do a water change.

Does this sound like the way to go or is there something easier?
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Lifetime Members
Lifetime Member
Jan 6, 2016
It can be done. Depends on how much work you want to do.

I store RO water for water changes, which is dosed, heated, and aerated.

Two 55 gallon drums located in basement. Ran Pex up through wall behind tank. Keep a pump both in the aquarium and in the holding tank.

One switch water is pumped down to the basement drain. The other switch water is pumped up from the holding tanks.

And when you are changing 125G, the more automated you can make it the better.

Pics of my holding tanks and RO system on first page of my journal here..................................