I have a tank with vals and some christmas tree moss growing under 2.4 watts per gallon. My water is very hard and very alkaline.
ph-8.2-8.5

I have been battling what I believe are hard water stains on my aquarium glass (lots of small white dots that only come off with a razor blade). I have been having trouble with my vals lately because they are starting to get the white spots on them too.

I currently have 4 tanks, all with the same water source, but only this tank is having trouble with hard water spots. I've tested all the parameters and nothing is out of the ordinary. How do I combat the hard water stains? Has anyone ever heard of hard water stains on plants or am I dealing with something else? (please don't default to snail eggs. I've had puffers and bred LOTS of different snails and it isn't eggs)

Thanks!

It's likely to be calcium deposits. It can happen in hard water like yours; you can get it off, but unless you change your water chemistry it's likely to continue happening.

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Makes sense to me.

What do you think would be the easiest, safest way to alter the water chemistry?

I'm thinking of using RO water to bring the PH, alkalinity, and hardness down, but I realize this is gonna be a pain for keeping stable water conditions with water changes.

The most puzzling thing about this situation is im only getting these deposits in my planted tank!

What exactly are you kh, gh and pH values?

I suspect you have something other then snails but still livestock from the plants.

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

GH- 220ppm
KH- 280ppm
PH- 8.3

that may be a bit high and a little reversed with kh more than gh.

But seems possibly ok especially if the fish are fine.

Might try a pinch of epsom salts to bump up the gh a bit.

then see if the kh comes down also.

if not after that try a bag of peat moss in the tank to see if the brings thing more in line.

Or do nothing and just look at the interesting white spots.



my .02

__________________
fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

Maybe another piece of the puzzle? Found it on Biogenic Decalcification



chicken and Egg?-biogenic decalcification
by krombhol/teclink.net (Paul Krombholz)
Date: Sat, 25 Apr 1998
>Larry Frank wrote, Friday, Apr. 24:

>....So this is sort of a chicken and egg question. Does the rise in PH due to
>CO2 being pulled from solution cause biogenic decalsification. Or does
>biogenic decalsification cause a rise in PH?
>
Plants like Elodea, Najas, Eigeria, Ceratophyllum, and Vallisneria are able
to utilize the bicarbonate ion, HCO3-, They remove CO2, leaving behind
OH-. The high pH created causes precipitation of calcium carbonate on the
leaf. The increased OH- drives the equation, HCO3- -------> H+ + CO3-- to
the right. The H+ combines with the OH- to form H2O, and the CO3--
combines with Ca++ to precipitate out as CaCO3.

Paul Krombholz, in cool central Mississippi, where it is going to get
warmer.

Although I'm not one to believe everything on the internet, seems to clear up quite a few things. I found this in a previous thread about this same topic.

"First: bicarbonates, or perhaps more scientifically correct as hydrogen carbonate (HCO3-), is an intermediate form of carbonic acid. Bicarbonates are higher in hard alkaline water. Plants can obtain carbon from CO2 (carbon dioxide) or bicarbonates, though they often have a preference. Most of those in aquaria are soft water plants that prefer CO2 because it is less work for the plant to extract the carbon. Plants such as Vallisneria, Egeria, Elodea and Myriophyllum (to name only a few) which naturally occur in hard water are better at using bicarbonates. Some, such as the mosses, the Pygmy chain sword, Ceratopteris, Ludwigia, and several others cannot use bicarbonates at all. [There is a list if you're interested in Walstad, p. 97, with the reference to the scientific study that determined this.]

Interestingly, many of the amphibious plants [the bog or marsh plants like Echinodorus, Cryptocoryne, etc] cannot use bicarbonates well, and it is hypothesized that they use the aerial strategy (emersed leaves) to supplement their carbon uptake.

Plants use bicarbonates much less effectively than algae. This is probably part of the reason that algae tends to be worse in hard water compared to soft, all else being equal.

Now with the background understood, I will cite directly from Walstad to define biogenic decalcification since this is highly technical and beyond my comprehension:
Some bicarbonate users polarize their leaves during bicarbonate uptake. Polarized bicarbonate uptake has been described for Potamogeton lucens. The plant excretes H= (acid) on the leaf's underside to generate a pH of about 6. The acidity converts bicarbonate to CO2, which diffuses into the leaf to be used for photosynthesis. In order for the plant to maintain its internal charge balance, H= is taken up by the plant on the leaf surface resulting in a high, localized pH (about 10) and a high hydroxide (OH-) concentration.

The OH- combines with calcium bicarbonate [Ca(HCO3)2] in the water causing the precipitation of calcium carbonate (CaCO3) on the top of the leaf. In hard, alkaline water, this reaction, which is called "biogenic decalcification," may be so great that crusts of precipitated CaCO3 may weigh more than the underlying plant. I have seen CaCO3 deposited as small white "pimples" on the leaves of Egeria densa and Ludwigia repens when they were grown in hardwater under intense light.

Some aquatic plants (e.g., Myriophyllum spicaytum and Vallisneria spiralis) that use bicarbonates do not polarize their leaves during bicarbonate uptake.

There we are."