Costa Rica Plaster/concrete pool trouble

[palmettomoves]

I'm leaving on a vacation to Costa Rica shortly and have been pegged to assist in some pool maintenance while I'm down there. For background this is an inground pool at a private home made of concrete or gunite or plaster. (I'm only slightly familiar with the differences in these because my pool is vinyl.) I'd say the pool is about 15 000 gallons. It was a saltwater pool but I'm told it's operating on chlorine right now.

So here's my role. Apparently they periodically drain the pool, brush it because of dust, repaint it blue and refill it. I'm going to assist in this process on my visit. So the problem we're attempting to resolve here is the dust, which by the sounds of it must be bonded to the pool if we have to brush to remove it. I presume this is because the calcium level is not kept at the appropriate level and it is dissolving out of the plaster??

My questions are:
* Is it too little calcium in the water or some other problem?
* Is it necessary to drain the pool to remedy this?
* Can this be avoided in the future?
* Is whether it's gunite or plaster or concrete significant or are they all treated the same?
* Anything I have to consider in light of the fact it is in a tropical climate with lots of rain?

Any tips would be greatly appreciated.

Signed
Knows Enough to be Dangerous.

 

[Bama Rambler]

If it's calcium scaling, (which it sounds like) then it's most likely too much calcium. IF you can get a set of test results it'll help determine what it may be. As to whether you need to drain to take care of it, it all depends. Since it's a painted pool it could just be chalking of the paint and there's nothing you can do but, drain, brush and repaint to cure it.