I'm going to post readings for the water we are currently treating, so I can figure out what the best system is that I need to follow in order to get the results I want.

After water is run through RO:

PH - 6.8
Ammonia - 0
Nitrite - 0
Nitrate - 0
KH - 1 degree
GH - 1 degree

Tap Water Today:

PH - 7.0
Ammonia - .5 to .75
Nitrite - .25
Nitrate - 5.0
KH - 2 degrees or 35.8
GH - 5 degrees or 89.5

The Ammonia and Nitrites and even the PH are all surprisingly low today. Normally, PH hovers around 7.5, and Ammonia is 1.0 to 2.0, and Nitrites have been as high as 1.5 as recent as a few days ago. The weather is cooler, don't know if that has anything to do with it.

Is this gh/kh scale correct? I found it on www.sydneycichlid.com:

First number is degrees, second number is its equal gh/kh

1 -- 17.9
2 -- 35.8
3 -- 53.7
4 -- 71.6
5 -- 89.5
6 -- 107.4
7 -- 125.3
8 -- 143.2

Thanks for the readings Lola. I purchased a RO system for my aquariums and will be setting it up soon. What kind of minerals will you be adding to the RO water?

I'm using Kent's RO Right. I'll post my results a little later tonight. I know my problem will be that my PH will rise too high to get the KH/GH to 100.

Correction above - RO water PH is 6.6


Results of PH/gH/kH after adding "Kent RO Right" to 5 gallons of RO water:


1 level tsp.

PH - 6.6
KH - 1 degree
GH - 1 degree

2 level tsp's.

PH - 6.7
KH - 1 degree
GH - 1 degree

2-1/2 level tsp's.

PH - 8
KH - 1 degree
GH - 1 degree

3-1/2 level tsp's.

PH - 9
KH - 2 degrees or 35.8
GH - 2 degrees or 35.8

Can someone help me figure out what to do? For now, I am using 2 to 2-1/2 level tsp's. per 5 gallons of the Kent's RO Right, to keep my PH close to the upper 7's. I am not sure what to do about my soft water.

My plan is to put river rock in my aquariums....and it looks like that is a very good idea, according to the following:

To raise GH, add Epsom salt (magnesium sulfate). A baseline recommendation is 1 tablespoon per 5 gallons of water (dissolve in a cup of aquarium water if adding directly to the tank). While adjusting total hardness is not as potentially dangerous to your fish as adjusting pH, dramatic changes of any sort can be stressful. “Flashing” (rubbing on the gravel or rocks) is often attributed to changes in hardness. Personally, I would make any substantial GH adjustment over a period of 2 to 3 days if my aquarium were already stocked with fish.

Rockwork in your aquarium helps with hardness too. While the effects are negligible (except with limestone, which is mostly calcium carbonate and therefore works on GH and KH), total hardness is likely to be higher with rocks in the tank than it would be without. Limestone, Texas Holey Rock (also limestone), pagoda, tufa, lace, petrified wood, quartz, slate, marble, and even common river rock can all be used in your aquarium safely. Be sure to thoroughly clean and sterilize (boil) anything suspect before putting it in your tank.


I already know about crushed coral (I think I might just get some of the bigger pieces and scatter them around with the rock) for raising PH/KH, but didn't know what to do about the GH.

Does anyone use Epsom salt to raise GH? I don't think I want to try that.

I don't think I'd want to either. The only way a fish can excrete magnesium sulfate is via the kidney so over a period of time that would be an unecessary load on the fishes excretion system. For short periods its useful as a laxative or to encourage release of bodily fluids but long term that kind of duretic would not be a good thing at all I think.

The river rocks sound better. I've also heard you can run the source water through limestone.

That pH sounds unusual...... enough to make me question it a bit..... at least that would be a start.

What sort of pH test are you using? Do you have a source of clean, distilled water that you can use as a "base" reading - to see if your pH readings are close to "good" or if there might be a skew?

It is a bit unusual for a number to jump exponentially - though the pH scale is such!

Once again - your comment about people who take their nice tap water for granted is SO on the mark.....

Correct me if I'm wrong but maybe the PH and other water parameters will stabilize if the RO water is allowed to sit (aerate) for a day or so with the added Kent R/O Right. I bought the same stuff and the bottle says; "do not greatly exceed the recommended teaspoons even if your test indicates different". My city water supply is softened at the treatment plant and contains softening salts which I have heard aren't any good for fish. I purchased the Kent Marine Hi-S 60GPD a few months ago. I am currently planning my setup (hidden).

What kit are you using for the GH? Is it the kind where you count the amount of drops added? I had written a question of what is the gh supposed to be.

I'm using the API and Tetra kits, which show the same results, for the most part. What do you mean by the distilled water comment? How do I get that with my water?Tetra

There's no way to run my tap water source through anything before the RO. I even have well water that I use for my automatic sprinkler systems, but have no way of accessing it without having the person who installed it come out an modify it.

However, I was thinking.....

I want to decorate my tank with the river rocks scattered around the bottom, and 1-2 chinese statues. Maybe I could find statues made out of limestone? Do you think that combination would help stabilize my water params?

It couldn't hurt. I hope you get it all figured out soon! I know you have had such a hard time with this new tank. What an awful experience when you have had and you were so excited about getting this bigger home for your babies. I am sure you will get it all figured out.

Well, the 5 gallon bottle that I got the PH - 9 result on is still sitting...I'll give it a few days and see if anything changes.

Just beware limestone is a very heavy stone. I have always wanted to try sea shells in my tank! Great for buffering. Just masses of sea shells on the bottom...but they can have sharp edges and might not suitable for the kind of fish I keep. Limestone is made from the shell bed so has the same calcite properties. Coral is good too of course.

I found this so far, which is 19" tall. Do you think it would be too heavy? What would be considered too heavy I wonder in a 125g tank?




I have tons of crushed coral, which I had in the 55g before, and never had a problem with PH/GH/KH. But since removing it and going bare-bottomed, I have a much cleaner, easier to take care of tank. I did like the look though.

Whoa! That looks very heavy. Imagine dropping that on its side while cleaning risky..but I can see it would be very suitable for your fish and likely tank theme.

Thre is the old fashioned plaster of Paris pucks treatment........

My experience with the pucks: THe pucks work but tend to leave residue as they dissolve. My fish ingested it while foraging and it gave them a sticky white poo. I had cured the puck for 2 weeks before putting it in the tank. It's too bad because I liked the convenience of the puck.

I'm lost.

It would depend on width of the base. It's meant to go outside in a garden, so don't think it should be that tipsy. Although siliconing it in place would likely help.