chopstick1 said:
pool is 20ft by 10ft, sloping in the center with 3ft ends/5.5ft center. everything was fine until I ran out of trichlor tabs, chlorine level dropped to 0 and started using the trichlor plus tabs instead. here's the reading....
total hardness- very low
TC 0
FC 0
ph <6.8
alkalinity 180
stabilizer very low
some green algae on the walls despite 1 bottle 50% algaecide
is it possible to be acidic and have a high alkalinity? I checked it with 2 different brands of sticks and it's accurate
any ideas??
thanks
Yes, it is possible to have low ph and high total alkalinity. The two, confusingly enough, aren't the same. Your ph appears to be extremely low - 6.8 is the bottom of your measurement scale, and it is unknown how far below that your ph is, really. You should get some borax in the water now. As mentioned above, 20 Mule Team borax is the stuff.
Your ph needs to be between 7.2 and 7.8. Do this first.
Total Alkalinity is more of a measure of the resistance to ph change of your water. We can address that later.
As you know, you have no chlorine in your pool. As soon as you get the ph in range, you should dose your pool with liquid chlorine. The reason for not using tablets or powder is that every other type of chlorination product adds additional ingredients - dichlor powder and trichlor tabs (what you have been using) add CYA, and cal-hypo adds calcium. Liquid chlorine, sodium hypochlorite, or ordinary unscented laundry bleach, just adds chlorine.
And, since you have been using trichlor, it is highly probable that your stabilizer is not low, but quite high.
I will also again mention the need for a good test kit. Strips are notoriously inaccurate and often worse than no test at all. Pool store tests can be decent, but more likely are haphazardly done by people who do not care about good results using poor test equipment. In fact, the worse your results with them, the more money they make.
Do yourself a favor and get a quality drops-based kit, preferably one which has a FAS-DPD chlorine test. The only two I know of is the Taylor K-2006 and the TF100. The two are compared here:
pool-school/pool_test_kit_comparison
Note that FAS-DPD is different from DPD.
And welcome to TFP.