Magnesium Sulphate: is it necessary?

[dts_spawn]

is it necessary to add Magnesium Sulphate in the water? i read some where that it is not necessary because our PUB water has it already but one of the forumers i met says that the amount in the tap is not enough.

[juggler]

If you do regular water change frequent enough, it should be enough.

The amount of Mg and Ca has to be balanced. The ratio of of Ca:Mg is 3:1 or 4:1 or something like that.

If you have too much Mg in the water and insufficient Ca, the plants will exhibit Ca deficiency problem. (Ref: this AquaBotanic discussion)

So - if you intend to dose Mg, remember to add Ca as well.

Some of the forumers here use coral chips (those including crush shells) as a source of Ca and Mg. The ratio of Ca and Mg in the corals is about right so there's not much worries. Put the coral chips in a mesh bag in the filter so that they can be removed or the amount adjusted easily.

[kelloggs]

Sorry to hijack your thread dts_spawn. I have this query that hovers my head for sometime.

Juggler, I am wondering how many mg is one tablet (5 cents size) of Calcium bicarbonate? I need to know this so as to try out and adjust the proportion in accordance with your "golden ratio" for Ca:Mg. For Mg, i will stick to the instruction for dosage on the label but the tablet package does not say anything about the weight of one tablet.

My tank dimension is 4ft x 1.5ft x 1.5ft and according to the supplier, one tablet of CaCo2 per week after water change should be enuf... hope you can enligthen me.

I read the article from the link given by you and i believe my thank is lacking nitrate. The tank is 2 months old and the AAP test reading for nitrate is 0 ppm all this while. I bought Dr Mallick Calcium nitrate but dare not dose it as i am concerned in algae blooming.

So far, the stem plants need to be trimmed almost every week but the plantlet tiger lotus seems be the same size after 6 weeks...

Maybe there are somewhere in this forum, but i still haven't found it, i would be grateful if you could let me know the fertilisation regime you are currently adopting?

Light intensity- 8 x 36w PL - 10 hrs/day

[juggler]

Hi Kellogs,
I am not sure about the amount of Ca in the tablet. For me I use coral chips in my filter for my supply of Mg and Ca and it gives me about 4~5 dkH. They are about right in the ratio from what I found on the net. I read somewhere that if your gH is > 7 or so, there shouldn't be Ca and Mg problem.
Since you have Ca(NO3)2, why not use it?
My weekly fertilisation regime is: 10ppm K, 1.5ppm PO4. Traces using Lushgro-Micros daily. Lots of fish feeding daily for the NO3. That's about it.
You have a lot of light for your 4ft tank. Better ensure the macro-nutrients are enough.
kf