I'm looking for some enlightenment and I know there are some real pool experts on here, I'm trying to understand how the balance of my chemicals works.
Here is the scenario:
Pool is heated with automatic dosage of chlorine (sodium hypocholride) and dosage of acid (sulphuric acid) to maintain the ph balance.
I overwintered the pool by shutting everything down and adding a winterising chemical which should maintain the chlorine in suspension and reduce the freezing point of the water (don't have the name to hand)
I have started the pool and tested the chlorine and ph values - which were showing more or less correct : Chlorine at 1.8 ppm and ph at 7, water at 11°C. So instead of shocking the pool I just switched on the dosing system. The problem was that as the chlorine dosed the ph value was going down not up as I would have expected. I double and triple checked to make sure that I had not got my wires crossed (literally!) and recalibrated the probes for the dosing system - all to no avail.
I could not rectify the situation, so I have added sodium bicarbonate to up the ph value to 7 and have now shocked the pool - so chlorine is high for the moment.
Can anybody shed any light on why this was happening?
Understanding pool chemical balance
I would manually adjust the ph level as several things knock it off balance like:
rain
hi or lo chloro
changing water supply
The ph is critical as if it is off balance the free chloro won't work. Do it bit by bit so you don't overshoot.
If a test proves wrong, try again as the test may be off.
Good luck, at 11 deg it won't be going gree for a while.
rain
hi or lo chloro
changing water supply
The ph is critical as if it is off balance the free chloro won't work. Do it bit by bit so you don't overshoot.
If a test proves wrong, try again as the test may be off.
Good luck, at 11 deg it won't be going gree for a while.
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costablanca blue
- Posts: 13
- Joined: Sun Apr 14, 2013 6:02 pm
if you´ve got an auto pH system
the pH will always go down as it´s continuously adding acid.
be careful with this as a low pH can quickly erode pool grout.
a reduction in pH isn´t always necessary if total alkalinity is correct.
i´d recommend a google on the relationship between total alkalinity and pH in order to understand the subject better.
auto dosification of liquid chlorine is a great idea but i´d recommend manual pH adjustment in order to safeguard the condition of the grout
be careful with this as a low pH can quickly erode pool grout.
a reduction in pH isn´t always necessary if total alkalinity is correct.
i´d recommend a google on the relationship between total alkalinity and pH in order to understand the subject better.
auto dosification of liquid chlorine is a great idea but i´d recommend manual pH adjustment in order to safeguard the condition of the grout