First test - some help needed please

[Crunchy]

Below test results (Fresh Taylor reagents), I have a couple of issues I would really appreciate some help with....

pH 7.7 (Raises from 7.4 to 7.7 within two days)
FC 7
CC not tested
CYA 70
TA 120 - 130 (Range is results from multiple tests)
CH 420 - 450 (Range is results from mulitple tests)

Used 25ml tests where possible to provide greater accuracy.

Salt - not tested but believed to be within range (4000 - 5000)

The SWG running 2 x 3hours per day at 50%

Have completed tests in triplicate over a few days and the results are highly repeatable (I.e. consistent). The issues I have are:

1) Calcium flakes forming in the bottom of the pool below the inlet jets.
2) Rapid build up on the SWG cell almost immediately after cleaning.
3) Struggle to keep pH in check, have to add 500ml to 1L HCL every two to three days

Pool is peeblecrete (Concrete) about 15 years old and appears in very good condition (And I would like to try and keep it that way!). The pump / sand filter / SWG is about 8 months old and all working well with good water pressure - sand filter backflushed recently (Twice). Pool water looks good, nice and clear, slight smell of chlorine on the skin when get out but not too bad at all - much less than a public pool. Some irratation on the eyes is noticable.

I have access to about 10,000L of tank water (Rain) which I could use to dilute CH but worried about introducing algae into the pool as tank water very stale - could super chlorinate the water prior to adding to pool?

Any advice gratefully recieved as I am new to pool ownership.

Thank you
Crunchy

 

[Jezza]

Hi Crunchy and welcome back!

Good to see results posted with your Taylor kit (obviously it arrived in the mail).

FC/CYA looks fine so that is good. The first thing to do IMO is to deal with the high TA which should hopefully start to arrest the tendency for the pH to rise. Essentially bring your pH from 7.7 to 7.2 by adding 1.2L of HCL and then adjust your return jets so they point upwards. This will provide the aeration required to raise your pH but also bring down your TA. For further info read the 'Lowering Alkalinity' article in Pool School.
Your CH is on the higher end of the recommended level for your concrete pool, but getting the pH and TA under control first should be your first priority.

Oh and by the way use the 10ml samples which is accurate enough and will save you a stack in reagents!

 

[Crunchy]

OK thanks Jezza, will do exactly that - jets won't adjust enough to break the surface so I will make some kind of aerating device on the W/E - I saw some piccies on here somewhere.

 

[otter86753]

Jezza has you on target. A great tool on PoolMath to keep in mind is your CSI. You can play around with your numbers (Not actually adding the chemicals yet) to see if you can get a CSI in the 0 to -.03 range which will help with your scale issue.

 

[Crunchy]

Thanks Guy's

managed to to get the jets facing up after all, some reasonable aeration happening but not heaps, probably had about 9hrs running with the jets up and TA does seem to be coming down a bit, one part of the pool (Next to the jets) tested 90 and the other end 110. Have topped up the acid and pH currently at 7.4. Will test tomorrow with pH probe for more accurate reading.

 

[Jezza]

Good to see that TA coming down Crunchy. I would pitch for TA of 70 and then see how your pH is going from there-hopefully the pH rise will be starting to stabilise. Also hoping that this will start to make the calcium flaking issue subside as you your CSI gets closer to the '0' mark. Definetly worth having a look at the CSI part of Poolmath!