Chemical Imbalance in Salt Water pool

[Mike Conroy]

Hi. I live in southern Spain. I'm renting a villa with a salt water pool. There are no manuals and the landlord is very vague about how to maintain the pool.

I have an in ground salt water pool; with concrete sides & base and tiled surface; capacity = 65 c.m. (17k US gallons, 14.3k UK galllons).
The chlorinator is generic, labelled RP35 and, I believe, requires salt level of 4,500 ppm - 5,500 ppm.
Pump is ESPA Squiper 80M (max 15.8 cu.m. p.h.).
Filter has max capacity of 16.5 cu.m. p.h.

The landlord's plumber (the local pool expert) has been advising me but we're not really making any progress. His main concern has been to reduce the pH level first. So I'd like to ask people who know for some help please.

For the past month I've recorded the levels of the chemicals. They've fluctuated but the pH & Cl levels have never come down to the right sort of levels.
The pool has no CYA and my test kits only cover Cl, pH & salt levels.
Today the salt level is 4.6 (1450 ppm)
The pH is 8.0.
The Cl is off the scale.

Reading articles online I now see that the correct salt level is the first thing to correct. To get the pool up to 4,500 ppm would require 375 lb (170 kg) of salt (or 235 lb / 105 kg) to raise to 3400 ppm. Either way this is a lot of salt and, before I add it, I want to be sure that my plan is correct - I don't want an expensive mess to sort out later.
There is no CYA in the pool so I guess that my next steps will be to adjust the SWG % setting to keep the FC level in the 4 - 6 range.
Then adjust the pH with the addition of muriatic acid to get that down to 7.2 - 7.8.

Thank you, in anticipation, for any assistance.

[Denniswiseman]

Really what you need is a decent FAS/DPD and salt test kit
The average SWCG requires about 3000ppm but yours may be different and at 1450ppm probably won't work
You say the chlorine is off the scale, do you mean it's high or isn't registering
You really need to get some CYA in there

Check out
Chlorine / CYA Chart
Pool Levels
Pool Maths
Every thing in a pool is related
FC:
TC:
pH:
TA:
CH:
CYA:

Muriatic acid (hydrochloric acid) to lower pH and TA
Bicarbonate of soda to raise TA
Aeration will raise pH only
Soda ash will raise pH and TA

[Mike Conroy]

Really what you need is a decent FAS/DPD and salt test kit
The average SWCG requires about 3000ppm but yours may be different and at 1450ppm probably won't work
You say the chlorine is off the scale, do you mean it's high or isn't registering
You really need to get some CYA in there

Check out
Chlorine / CYA Chart
Pool Levels
Pool Maths
Every thing in a pool is related
FC:
TC:
pH:
TA:
CH:
CYA:

Muriatic acid (hydrochloric acid) to lower pH and TA
Bicarbonate of soda to raise TA
Aeration will raise pH only
Soda ash will raise pH and TA

Thank you Dennis

I have asked my landlord for the recommended salt level for the generic RP-25 SWCG; also if the pool is protected with CYA.

Th FC level is very high - more than 3, judging by the colour.

Thanks for the links to the pool chemistry pages. Very interesting. Clearly these are matters I need to understand.

I have made enquiries of US distributors of FAS/DPD kits. They appear to be unavailable in UK or anywhere in Europe.

[Denniswiseman]

Is this your SWCG
https://poolandspawarehouse.com.au/k-ch ... nator.html
http://www.kawanachlorinatorspares.com. ... l-4000.pdf
Looking at the manual it seems that 4000 is the number
A free chlorine level of three is not high it's a minimum with 5 to 6 being the optimum for a SWCG pool with a CYA 70 to 80
I had to get my Taylor K2006C from the states as well
Keep reading and learning and we will help where we can

[Mike Conroy]

Is this your SWCG
https://poolandspawarehouse.com.au/k-ch ... nator.html
http://www.kawanachlorinatorspares.com. ... l-4000.pdf
Looking at the manual it seems that 4000 is the number
A free chlorine level of three is not high it's a minimum with 5 to 6 being the optimum for a SWCG pool with a CYA 70 to 80
I had to get my Taylor K2006C from the states as well
Keep reading and learning and we will help where we can

Thanks Denis.

This is my chlorinator - https://www.amazon.co.uk/BSPool-RP35-Re ... B06Y2CMH19
It seems to be marketed as Autochlor or K-Chlor

I believe this is the manual - https://aiswater.com.au/wp-content/uplo ... Manual.pdf
If so the salt level needs to be 4500 - 5500 ppm?

In which case the level in my pool (4.6 = 1450) appears to be seriously low? I guess I should start adding salt?

Mike

[Denniswiseman]

That's great you've well on your way now that you know what you have
Use Pool Maths to work out how much salt to add
I work it out to raise to 5000 ppm you need 231kg of salt for 65000 litres
I wouldn't add all at once and test between so you don't overshoot
Order more as when you backwash, splashout, rain dilution will lower your salt content.
Evaporation has no effect as the salt is left behind
I would look on Ebay

[Mike Conroy]

That's great you've well on your way now that you know what you have
Use Pool Maths to work out how much salt to add
I work it out to raise to 5000 ppm you need 231kg of salt for 65000 litres
I wouldn't add all at once and test between so you don't overshoot
Order more as when you backwash, splashout, rain dilution will lower your salt content.
Evaporation has no effect as the salt is left behind
I would look on Ebay

Thanks Dennis

That's what I make it - quite a bit!

I'm in Spain and a 25kg bag is about €5 or €6. Deliveries from online shopping are hopeless here so I'll buy locally.

I will do as you suggest -I'm trying to get all the chemicals in balance so I'll add the salt in stages & monitor.

Thanks for your help.

Do you have a salt water pool?

M

[Denniswiseman]

Hi Mike
No my pool uses liquid chlorine but SWCG's are loved by the people that have them as once they are dialed in you don't have to worry about dosing daily especially when on holiday
They reckon the running costs are the same because they do burn out and have to be replaced which balance's out the monthly costs of chlorine, although you wouldn't have to replace it, your landlord would
Ideally it's reckoned to have one twice as big as the rated output for your pool so that it isn't running 24/7 at 100%

[Teapot]

Using stabilised salt rather than ordinary salt will get some stabiliser into the pool which you need. Don't use all stabilised salt or you may over shoot the level.
Test kits are available from the UK or I can ship to you in around a week if needed but it is imperative that the stabiliser level is accurately measured, this is more important than the pH