New house with Fiberglass Pool (16,700gals) 0 TA, well over 100+ CYA

[armyb77]

Hello,

We just bought a house with a nice fiberglass pool made by Barrier Reef. I just finished testing the water and have some pretty shocking numbers. PH is very low, but my TA is somehow showing as 0 or some number unreadable. I have the Taylor K-2006 test kit and some test strips. Everything is matching with both tests except for the CYA. The CYA on the K-2006 gets to the 1.8ml line and the black dot can't be seen, and the other test strip says it has no CYA. The TA being 0 for both.

My water is still crystal clear, but I know there are issues. I am just trying to figure out where to start. Do I do a water change? If so, how do you do a water change in a fiberglass pool safely? My last pool was gunite. I do not want to add 15lbs of baking soda to up the TA just to lose it with a water change. The FC is just about 1 after dumping 2 gallons of bleach in it.

Is the pool still safe to swim in, given its current condition, since the water is still clear?

Any suggestions to get things right would be appreciated.

Thanks,
Armyb7

 

[mknauss]

A TA of zero means your pH is very, very low.

I suggest adding enough baking soda to raise the TA to 70 ppm. Use PoolMath. Circulate and then test TA and pH again in an hour.
If pH is not readable post back.

Not sure I understand on the CYA test. Is it very high? So very little water is needed (before you get to the 100 line) to obstruct the dot?

The water is NOT safe to swim in until your pH is in the 7's and your FC is above minimum. See [FC/CYA][/FC/CYA]

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[mknauss]

You can exchange some water without draining.

If you place a low volume sub pump in the deep end and pull water from there while adding water in the shallow end (through a skimmer or into a bucket on a step so you lessen the water disturbance) you can do a fairly efficient exchange. That is assuming the water you are filling with is the same temperature or warmer than your pool water. If your fill water is much cooler than your pool water, then switch it. Add the water to the deep end (hose on bottom) and pull water from the top step.

The location of the pump and fill hose may change if you have salt water, high calcium, etc.
In my pool, with saltwater and high calcium when I drain, I put the pump in the deep end and hose in shallow end. The water in the pool weighs more per unit volume than the fill water from the hose.

Be sure to balance the water out and water in so the pool level stays the same. Also be sure your pool pump is disabled during this process. Once started do not stop until you have exchanged the amount of water you wish.