Sand Algae

[waste]

Ben, that's what I thought might be happening, though not with any technical reason. (I'm thinking this is in response to the 'calcified' liner question)

[waterbear]

I am wondering if this is a special type of algae or if the water balance is being pushed over the edge for scaling because of the algae giving off CO2 in their normal respiration and causing the the scale to encase the algae, which I suspect is the scenerio. I can see this happening if the pH is already high and the calcium is high. The localized increase in carbon dioxide in the water could be converted into bicarbonate under the right conditions and cause a localized scale deposit around the CO2 'bubble' and create what seems to be a 'grain of sand'. I have been searching and searching and cannot find any references to fresh water calciferous algae although it is very common in seawater aquariums and coral reefs.

[PoolDoc]

Waterbear,

I thought the same thing, at the time. I even had created a web page for PoolSolutions to explain this mystery algae, anticipating that it would answer a lot of people's questions. Instead, I found nobody had questions, or even recognized it.

And what's weirder is, was seeing it a number of times in 2001 and 2002, but never since. So, I don't know.

Ben

[waterbear]

because, as you said, they produce a thin capsule around the algae (which I asume is the CO2 bubble that algae can produce) and from looking at the pics where the capsules do look like bubbles made of scale I really do think this is something that happens under certain water balance conditions. It is reinfored by the fact that you saw it during a specific time period (and I will guess that the calcium levels in the local fill water or the alkainity or both were higher than normal at that time). Right now in my area calcium levels are much higher than normal because of our much lower than normal water table.

[waste]

While I'm not the chemist y'all are, this sounds reasonable.

Evan, always good to 'see' you , my friend