[Wet Thumb Forum]-Calcium dosing to increase GH

[javalee]

Thanks for the link Betty. I like Koivet as a disease resource but would've never found that explanation. I do have a KH of 20d despite my 0dGH tap water so I guess I'm getting calcium carbonate ppt. With a pH of 8-8.6, I wonder if most of the Ca and Mg that is "disappearing" from my GH test is being sequestered from the plants that way.

[dwalstad]

Once again, we can all learn something from the pond folks. Thanks Betty! I hadn't thought about adding Ca and Mg to control pH swings. Interesting.

[DataGuru]

Definitely! It's amazing just how complicated water can be! LOL

[Jane of Upton]

This is a great thread!

Always one to comparison shop, the price of CaCl varies widely.

Most expensive, I found Turbo Calcium at Doctor's Foster & Smith for $15.99 for 800 g. (1.76 lbs). That's $9.08 per pound.

Next was a home brewer site (Perfect Brew Supply), at $2.90 lb

Least expensive was GregWatson.com, charging $2.17 per pound.

Of course, I didn't calculate in shipping, but it was very interesting to see the spread of prices!

-Jane

[javalee]

Jane, I thought that buying from NorthernBrewer.com was great because I could buy only 2 ounces instead of a pound of the stuff! Of course, I only have a 10g tank.

Oddly enough, I measured today and the GH is down to 3dGH again! Nothing is ever simple in a natural aquarium!

[flagg]

Ok so I went ahead and finally read through this entire thread since I tested my water this afternoon and noticed that my GH had gone down to 0-1 dGH. I checked my Aquarix log and saw that the GH in this tank was at 8dGH on 10/26/05. So there's obvious been a steady decline and I should have seen this coming for the dGH was at 12 on 10/05. So the first thing I learned is that I should be testing my water more often! I'm pretty sure that I've tested the hardness in this tank since then, but don't really remember... Anyhow.... since reading this thread my head's still spinning and I just want to recap what my options are. As I see it, I have two:

1. add CaCl2 and MgSO4 in the manner describe above to achieve a 4:1 ratio and a dGH of around 8, OR
2. use Seachem's Equilibrium per their instructions to raise the GH to around 8.

All things aside, can I assume that it just comes down to a matter of preference?

One last thing, Diana mentioned to raise the GH if the plants are not growing well and the GH is low. My plants appear to be growing quite well, should I even bother?

-ricardo

[Dave P]

Ricardo,

Are all of your plants growing well? Didn't you recently have some H. polysperma that had holes in its leaves?

I seem to recall that you placed some cuttlebone in your substrate a while back, primarily for your Vallisneria. Perhaps the other plants are benefiting from this as well.

If your plants are truly growing well and the snails are not showing signs of calcium deficiency (weak shells), then perhaps you do nothing and just keep an eye on things.

Having said that, I believe many aquatic plants possess mechanisms to store some nutrients for leaner times. Perhaps your plants are currently living off of what they've accumulated over the past couple of months. If that's the case, these nutrient stores may become drained over the next month or so.

The last paragraph is speculation on my part and could be completely wrong; validation would be most helpful.

As far as which method should be used to raise GH, that needs to be your decision. I personally favor water with a mixture of anions over something that has a larger sulfate ratio. But that is conjecture; more experimentation is necessary. I think this thread does a pretty good job of illustrating the potential pros and cons of either method.

Just my thoughts,

Dave

[dwalstad]

Originally posted by Ricardo V.:

One last thing, Diana mentioned to raise the GH if the plants are not growing well and the GH is low. My plants appear to be growing quite well, should I even bother?

-ricardo

Dear Ricardo,

If your plants are doing well, then I would relax and just enjoy your aquarium. If new plant growth becomes poor, then you can officially start to worry. The nice thing about plants is that they're on a slow time table; there's plenty of time to remedy potential problems.

[dolce_ardore]

This is a very interesting and informative thread. Thanks to all for contributing.

I live in an area with <2 dGH water and very recently being trying to determine the best way to increase it to approach the recommended value of 8 dGH.

My first attempt has involved adding enough Seachem Equilibrium as per the product instructions to raise the dGH by 6 degrees, which for my 25g tank (let's say 20g water net) I estimated to be 32g (each 16g is said to increase dGH by 3 degrees in 20g of water). However, I lated discovered, based on other information such as the "FertFriend" tool, I've added the following nutrient concentrations:

62.4 ppm K >> [10-20]
25.792 ppm Ca ~ [10-30]
7.712 ppm Mg > [2-5]
0.352 ppm Fe >> [0.1]
0.192 ppm Mn

where the numbers in brackets are the recommended ranges, taken from Fertilator.

It's evident that the stated level increases from adding Equilibrium are far higher than the recommended ranges, with the exception of Ca, assuming all nutrients are added in the appropriate forms. It would therefore seem, on the surface of it, that using Equilibrium to increase dGH by more than a few degrees can cause a significant nutrient surplus, which may or may not have negative effects.

I also believe there was an increase in my pH, presumably due to an increase in KH, though I didn't measure pH and KH immediately before adding the Equilibrium. In a CO2 tank having the pH go up due to increased KH is fine since it will be brought down again by the CO2, but in a non-CO2 tank such as mine, an increase from my tapwater's nominal pH of 7 is not desirable.

These observations would seem to suggest that following Diana's method for increasing GH is better than simply using Equilibrium.

Further on the subject of CO2, I am wondering something else... To what degree will the addition of the Equilibrium detract significantly from the accuracy of calculating CO2 concentration from pH and KH using a standard table/graph (due to unaccounted buffering)? What about Diana's suggested method of adding only CaCl2 and MgSO4?

David

[DataGuru]

Interesting info.
Dunno on the Equilibrium, however, adding calcium chloride and mag sulfate shouldn't affect being able to derive CO2 levels from pH and KH.