Need help with hard water.

I need some help keeping down my KH and GH in my 75 gallon planted tank.
My tap dKH is around 15 and my dGH is 18 (have hard well water and changes weekly). I have been using Aquarium Pharmaceuticals Tap Water Filter, it dose a good job of dropping my dKH and dGH 1 or 2. Of curse I mix my water 50/50 with tap witch puts it at 9. My tank keeps readings of 12 dHK and 13 dGH.

The tank is set up with; tank was set up 4/01/04 and planted 4/16/04
-80 lbs play sand
-40 lbs Flourite
-20 lbs Onyx sand
-30 lbs Fine gravel Natural colors
Magnum 350 using lava rock in the media basket and a soft water pillow.
Large California grapevine
Medium, South Africa driftwood
-4 40watt tubes 2 Plant & Aquarium and 2 Daylight Deluxe 11 hours a day
-Cable heater, 100watt
-1 Visi- Therm Deluxe 250 watt
I’m using DYI Co2 till I update my lighting.
Lost of stem plants, some “rotted plants”
About 20 smaller Tetras

I took some samples of my Flourite, play sand, Onyx sand and gravel. The Onyx was the only thing that the vinegar bubbled up with. Will Lava Rock keep the hardness up?

What options should I look into for lowering hardness down? I would love to get my dKH and dGH around 9 to 6.

I have thought of removing all my gravel down to the play sand and rising out all the Onyx sand.
Getting a Magnum 250 and stuffing full of Peat.
Start using “Tank Soft” but then would need a second filter to help remove the calcium clumps.
Any other thoughts out there?

The water is right where I want it in my 55 gallon storage tank but then goes to he11 in this fish tank.

So I’m thinking then I should get rid of everything but the play sand and my large gravel and toss some smaller gravel back in to the tank.

The PH is not that bad it’s only 7.8 with the DYI Co2.
The filter would do better if I used it at 10 gallons per hour. I run it a bit faster.

My Pacu loves the water.


Thanks for the info on the Flourite raising the hardness.

Well it’s all got to go but the play sand on the very bottom for my cable heater. I know there is no easy way of doing this, but dose someone have any ideas to help?

I was thinking of netting 20 fish and putting them in 2 20 longs till the water clears back up. But that’s a pain in the back, then netting them again to restock the tank.

Dropping the water level about 6 inches using a peace of arctic (with no holes) to separate the tank into 2 parts and just do ½ at a time. Use a second filter with a micron filter to speed up the cloudiness in the ½ I working on.


I guess I will go with Fine gravel Natural rock as long as it dose not foam up on vinegar test. Anyone have any ideas to help me out?

Then what do you think is causing my KH to go up so high?

I guess the grapevine will be on its way out soon. Drift wood should slowly buffer the KH down I thought, real slow. The only thing I thought of is that I use Green Light Stump Remover, Flourish, Fleet Enema, and No-Salt. The only that a descent amount of is the Stump Remover. The rest are in very small doses so I don’t think it could be them.