Best method to increase KH without introducing Pho

[Nexstar]

I have a newly established planted tank and want to adjust the parameters for best CO2 for the plants.
Presently my readings are
Ph 6.3
KH 1
GH 5

I believe that I would prefer to have them at
Ph 6.5-6.7 Preferably 6.7
Kh 4 if Ph 6.5 5 if Ph 6.6 6 if Ph 6.7

My tap water in So Cal is high in Ph and Hard Kh 12 Gh is out of site.

I set my tank up with RO with RO riight to replace missing essentials. This is why I have nice low Ph and Kh
I believe that baking soda will increase hardness but I am not certain if it increases Gh or Kh. I believe Kh. If this is the best method let me know. I have considered increasing with small amounts of tap to bring up but I don't want to introduce all the ugly stuff in our tap water.

I will be running tank with a Ph Controller and a carbo plus to insert Co2. This is a small tank and this should work well. Volume of water is 21 gallon. It has 64 watts of flour lights running 11 hours a day. Currently one pink & blue 12000K and one blue & blue 12000K. I believe this is too much light and am going to keep the same wattage but change the spectrum to
Pink & white 8000K combo bulb and white& white 8000K combo bulb for the second one.
The substrat is pure Flora base minimum of 1.75" deep and over 2" deep in many areas.
I am filtering reverse flow thru an undergravel filter plate from the return side of my Eheiim 2126 Pro cannister and also using a Rio 50 head to move the surface water without actually rolling the water over just keeping it moving. So as not to remove excess CO2.

Any recommmendations are appreciated on how to safely and accurately increase Kh and what would be optimum settings.
I realize that it will flucuate during the day and night due to CO2 being produced at night and removed from the water during the day. That is why I will run the carbo plus off the Ph Controller. If I just ran it off the same timer as the lights I would have no control on PH during the day time, however it would prevent Ph spikes at night. The controller would also help keep the CO2 vol level so at night when it increases it doesn't get to dangerous levels. Hopefully the Oxygen generated during the day will be far in excess of what would be needed to get through the night.

Thoughts, suggestions, etc most welcome.

Thanks
Bob

 

[Bangin]

I use baking soda to increase the KH. There's a measurement of 1 teaspoon per 10 gallons, or so, that will increase the KH by 4 degrees. Some people use crushed coral to increase the KH.

I've seen the PH controllers, but I don't have any experience with them. I just turn the CO2 off at night to avoid dangerous spikes.

Edited to add: I use much less than 1 teaspoon per 10-15 gallons. It really depends on your own setup and what's best for you.

 

[Bol]

For probably more info than you are looking for ,

GH in an aquarium is basically a measurement of calcium and magnesium salts in the water. Technically not true, but a pretty good generalization.

KH (carbonate hardness) is the measure of carbonate and bicarbonate ions in your water.

Baking soda (sodium bicarbonate) will not change your GH, but will obviously add carbonates, so adding baking soda will cause your KH to rise.

When your KH rises, your pH will rise, too.

Just about everyone will recommend a KH value of between 3 and 6 degrees for a stable tank.

I've seen a few calculations for baking soda and KH, but the one I trust most is close to the one Bangin mentioned. It goes:

1 teaspoon of baking soda will raise the KH of 50L (~13 US gallons) of water by 4 degrees.

As side notes, ...

I think you're doing the right thing by removing some of the blue bulbs. Your plants will probably be better off with "lower K" bulbs.

I have no experience with them personally, but I've read quite a few bad things about the CarboPlus system, particularly with their maintenance.