How should I treat my hard water?

[KYRph]

I’m getting ready to set up a tank and I have been doing some preliminary testing of my tap water (city water). The tank will be heavily planted and will be the home to espei rasboras, juili corys and probably some Kuhli loaches.

KH: 40 ppm
GH: Highest reading on the strip
TDS meter reads 324
pH meter reads 7.2 directly from the tap

I have already purchased an RO unit to mix with the tap water but I’m concerned that since the GH is off the charts and the KH is relatively low that I will bottom out the KH and then have to add crushed coral and possibly other additives. I know it will be mostly trial and error but does anyone have any suggestions?

Thanks

 

[Chanyi]

Are you dead set on blending Tap / RO? Would you consider going full RO?

If going 100% RO:

Per 1 US Gallon:

0.386 Grams CaSO4 - 30ppm Ca, 4.2 degrees GH
0.384 Grams MgSO4 - 10ppm Mg, 2.3 degrees GH
0.135 Grams KHCO3 - 14ppm K, 1.0 degrees KH

Should yield:

6-7 degrees of General Hardness (GH)
1 degree of Carbonate Hardness (KH)
7.1 – 7.2 pH


Or, you can blend Tap:RO to achieve your desired GH and then just bump KH up by 0.75 degrees or so using KHCO3.

Also note: Your pH must be taken after tapwater has sat out in an inert container for 24 hours prior to testing pH. in most cases, CO2 will off-gas and your pH will climb to it's true value.

 

[KYRph]

Thanks for the information! I’ve actually considered doing full RO and using something like seachem replenish. Might be best. Thanks again!