Singapore Water - Ca & Mg content

[FC]

Singapore's water, I think, has 3~4 degree GH at most places.
Does anyone knows the Ca vs Mg composition?

Thanks.

[juggler]

Not sure. The info at http://www.pub.gov.sg/ws_potable_water.htm did not state Mg.

However, it seems that the NEWater contents at http://www.pub.gov.sg/NEWater_files/...ity/chart.html do not have Mg.

The gH at Boon Lay area is 3 dgH.

[geoffrey]

According to Mr Han, Chemist at Woodleigh's Waterworks Lab, The Mg:Ca ratio is 1:4. Hence at their specified total hardness range of 50-100mg/l, Mg is 10~20mg/l and Ca is 40~80mg/l.

Gwee, you think you can confirm?

[PeterGwee]

Geoffrey, I work in a WRP...not waterworks..LOL. Unless I seek help from my boss that is..why not write in to PUB. (I didn't try as my boss would as me why I want to know? Hahahahha..cannot find good enough reason to relate to work lah.) Newater conductivity is high enough to absorb all kinds of minerals from washoff of the reservoir banks. Do make some noise if they don't respond to your mail...its always like that one lah...you know lah..government staff always abit slow and only rush when complain comes in.

Geoffrey, pose it as a question like a....I'm a student of NUS and am working on a project need a breakdown of minerals and its concentration found in our tap water...N-NO3 level, PO4, Ca/Mg ratio...the rest are pretty much stated...PO4 is actually less than 0.1..need to dose definitely.

[vinz]

Errr... why go thru all that? Just write them an email and ask in a straight forward manner, citing our interests as aqua-gardeners. In fact, Geoff, how do you get your info? Did you write them and Mr Han replied?

And Peter, why don't YOU write in and ask? No offence meant, just wondering why you have to go through such a roundabout way?

[PeterGwee]

Vinz..actually I did write in at one time and as expected, there was no reply what so ever. You know their respond time lah...pretty much low efficiency unless you make lots of noise and treaten to complain. []

[geoffrey]

Vinz, I called him and told I keep fish and like to know.

He said they don't take Ca and Mg readings but he has some data on Ca in our water which he thinks is fairly reliable. As for the other 20% in the gH, he said we can assume Mg. Since he said "fairly reliable", I thought it best to confirm.

[vinz]

Well, if they don't take the readings, then no point writing in. Anyway, if that's really the ratio, it's good enough for most plants, except not enough. May explain why some tanks only bubble/pearl after water change.

Anyway, I've gone back into dosing Seachem Equilibrium which will provide K, Ca and Mg.

[geoffrey]

Could the bubbling after water change be due to that thick layer of protein being removed, making it better for light to get to the plants. Or, since most of us replenish our nutrients after water change, everything is balanced.

[FC]

The extra bubbling seen after water change may be due to the floride, one of the plant stimulus, found in our treated water.

[Sky Devil]

MG is magnesium?

[vinz]

Lyon,

I don't know what is MG, but Mg is magnesium. Next time check the glossary thread in the Aquatic FAQ forum, ok?

[Plantbrain]

Many water dept's don't test for Mg, Ca yes, but seldom Mg. They often blow it off unless you bitch since they don't really have an answer and are leary of folks asking about stuff they don't test for. They don't like saying "well we don't test for this" etc. That does not instill confidence in the public's eyes. I'ce gotten the same response here etc for a number of inorganics like PO4, Mg, B, K etc
What I did was look at these nutrients from their annual reports(often they out source to some lab for critical comprehensive analysis) and looking at many different tap waters, you get a good feel for general trends.

Your GH's sound great, not too little if you don't plan on adding any GH builder but also right at the threshold to play with higher GH's also.

It's easier to add something than remove it
4:1 Ca:Mg sounds right. As long as you do regular water changes, adding GH should not be required.

My tap is ideal, GH 5 KH 3.
I don't have to do a thing.

One thing you folks might try:
Use dolomite instead of CaCO3 since it'll add some Mg also and add a small bag to prevent depleation of GH.

Regards,
Tom Barr