Q We have a crushed aggregate surface on our pool, and it had been perfect until last year when a few rust-colored spots started appearing. This year, it has become much worse, and our pool-maintenance company says many pools are having the same problem.

The company thinks an acid wash may remove the stains, but we are reluctant to have our pool drained until we know what caused this and whether an acid wash would work. What are your thoughts?



It is difficult to know what is going on without seeing the pool. It doesn’t sound as if the steel reinforced rod is coming through the interior finish because there are a lot of spots. The stain could be caused by the tannic acid in leaves or the iron in fertilizer pellets or several other things.

We suggest you allow the pool-service technician to try and remove one or two of the areas of spots with a topical stain test kit without emptying the pool. We think it is important to diagnose the nature and source of the spots before the pool-service company drains the pool. The same problem may return.

Don’t try to drain the pool yourself to fix the problem. The results could be disastrous. Without water, your concrete pool will almost certainly float out of the ground. This is because the pool has no weight to hold it down against the water table.

Once your pool has taken on a new slant in your back yard, even filling it up again will not cause the pool to resume its previous location. Solutions to this problem include tearing off the cracked deck, pouring a new deck or ripping out the entire pool and deck and starting over. This would be costly.

Always have a licensed pool professional, who has a separate insurance policy covering pool popping, to equalize the pressure in and around your pool before attempting any resurfacing or repair work.

As for the rust spots, you want to make sure that any solution is not a temporary cosmetic fix that could cost you more later. Any improper treatment of the spots may damage the interior finish and also make you pay an unnecessary water bill for the refilling of your pool.

Pay for a second or third opinion; consult more than one licensed and insured pool professional in your area and ask the same questions before making your decision. (KRT)