Tezak

I have a 50 gallon tank which has had fish in it for a month. I now have 23 fish ranging from Barbs to Ottos, with just a few Java fern bunches for plants. I have a big shipment of plants coming in this week (30 plants), and my DIY CO2 system is now 50% running (1 of my 2 reactors are going).

My pH is at least 7.6, possibly higher, my kit only measures that high. My KH is at 9 degrees, or about 150 ppm. I want to lower both of those, since I think most of my fish prefer a pH around 7 and a KH around 6 or lower.

Any suggestions for lowering those two factors?

ashappard

the easiest way to lower KH (and pH in the process) is to add distilled or RODI water.
Another method is peat in your filter or use an acidic based substrate like ADA aquasoil or florabase. In this way you will remove KH and soften the water.

the easiest way to hit a target KH is to add the distilled or RODI water until the desired KH is reached. Attempting to maintain a specific KH or pH can be a slippery slope if the aquarium is not stable/settled. Adding chemicals to control pH (pH up / pH down for example) is not recommended for planted tanks.

Another way to give the fish what they need is to consider maintaining TDS rather than pH or KH. It is method of control that has good results both for the fish and plants.

ncutler

Too funny, I'm looking for the exact opposite. Tap water has 0 KH and 7.4 Ph thus making my co2 injected tank 6.2-6.4. Good luck with your challenge.

Diana K

Test in a bucket: Reverse osmosis water + tap water.
Try to find a mix that gives you the result you want. Test the TDS and GH, too.
If the test results you posted are TAP water, then you will want around 1/3 RO + 2/3 tap water. Perhaps 50% RO.

Then: Once you have found a mix that works change the tank over SLOWLY.

Fish cannot tolerate a sudden, sharp drop in total dissolved solids.

For example, figure out a blend and water change % that will drop the TDS by not more than 10% each water change. You might do 2 of these water changes per week, but not more. One a week is safer.

Without TDS meter go by the GH. Drop the GH by 1 degree per water change, maximum of 2 such water changes per week.

(If the tank needs more water changes then make as many as you need with water that matches the tank for TDS, GH and so on).

Fish are less concerned about KH and pH than they are GH and TDS.
GH includes calcium and some soft water fish cannot survive in water with too much calcium.