Aquatic Plant Forum banner

gh, kh, alkalinity, calcium hardness

4911 Views 5 Replies 2 Participants Last post by  shalu
I have these 4 test kits. The gh, and kh test kits are aquarium pharmaceutical test kits and the alkalinity and calcium hardness are lamotte test kits. My question is whats the difference between all of these test kits? I mean I know that kh and alkalinity are the same as they measure about the same with the ap kit reading at 4 degrees kh and the lamotte reading 64ppm(3.5dKh). However, my gH reading is a whopping 19dgH from the ap test kit and the calcium hardness kit reads 174ppm or 9.77degrees if this is actually gH. Does this mean to say that calcium hardness and gH are different? The reason Im asking this is because I want to calculate my mg to ca ratio and am now severly confused by not only the pps article but also by the ca:mg ratio calculator. If anyone could shed some light on this topic it would be greatly appreciated.

By the way by my misjudgement I dosed some Kent gH+ yesterday which may be responsible for the super high gH reading from the ap test kit if that helps at all.
1 - 6 of 6 Posts
GH contains both calcium hardness and contribution from magnesium. In your case:

Ca = 174/2.5 = 70 ppm (174 is for CaCO3, we divide by 2.5 to get actually Ca number)
Mg = (19*17.9 - 174)/4.1 = 40 ppm (we divide by 4.1 to convert from CaCO3 number to Mg number)

**Corrected 17.1 to 17.9
Hey Shalu
thanks for the clarification =). So according to your calculations I have a ca:mg ratio of 1.89:1. Is this a good level?
I would not worry about the ratio unless you see Calcium deficiency (wrinkled, twisted, bent leaves, leaves are possibly smaller, stunted) symptoms on some plants. I corrected the calculation a bit.
Hey Shalu

actually I have been noticing that on occasion I do get wrinkled and twisted leaves. I think now that problem isnt so prominent but I have been notcing that my ludwigia spec cuba leaves are getting awfully pale. Here are some other water parameters which are for a 20 gallon tank:
pH 7.5
NO3 10ppm
PO4 1ppm
Fe I dose 2.5ml every other day
Flourish I dose 2.5ml on the days I dont dose Fe
K on this one I actually have no clue as to how much I have. I dose this occasionally and dont really keep track of it(I know I know I should and I think I will start now).
Lighting is by way of 2x55watt power compacts 1 6700k and 1 9325K.
As far as CO2 goes Ive just been dosing Excel 4.5-5ml everyday and the plants are actually pearling.
So far the only problem Ive been seeing is the discoloration of leaves on the Ludwigia cuba and the occasional wrinkle in the leaves here and there. So Im kinda confused. I thought it could be my Ca:Mg ratio but Im guessing that thats not the issue?
See less See more
I was just saying if you don't see any wrong with plants, then don't worry about it. Now that you say you do see those problem, then I think it IS calcium uptake problem. I had the same problem, so I added CaCl2, helped a lot. I got pale color on 'cuba' before I dosed more Iron/trace. I use close to 100 ml trace on my 100 gallon /week.
1 - 6 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.