Tight water chemistry specification for fibreglass pool warranty

[JoyfulNoise]

Potassium and magnesium chloride will be equally corrosive … it’s the chloride ion (Cl-) that causes enhanced corrosion (crevice and pitting corrosion), not the cation. Either way, pH has the biggest influence on metal corrosion and so if you keep the water properly balanced then there’s nothing to be worried about. Salt water pools are “brackish” at best, not seawater.

 

[AUSpool]

Thanks Auspool,

specifically for the AS quotes. That is the missing piece of the information puzzle for me. it just confirms how ridiculous the warranty ranges are, given the STABIKISE at 30-50 and FC >3. Makes a mockery of the warranty figures, doesn’t it.

I wish 31 degrees was inevitable. Southern Victoria is not quite Brisbane! one can only hope though. It’ll be great problem to have.

yeah, I’m starting to lean back towards NaCl. i didn’t overly mind a mild cost increase, especially if it meant less potential corrosion from NaCl, but if it just adds a new set of potential issues and complications, especially staining, I might as well keep it simple and go for a NaCl chlorinator.

30-50ppm is quite standard for CyA, industry standard that is. Although the dichlor and trichlor manufacturers would like that raised to 200ppm+. 1-3ppm FC is a common industry range although 1-4ppm is also used. The industry treats CyA and FC as independent values which is wrong when you understand the chemistry which they (the industry) should. I keep my FC at 10% of my CyA.

30-31C through a VIC summer won’t be uncommon but remember there are a lot of heated pools, both FG and concrete.

There is a lot of fancy advertising in the pool industry. When it comes to salt it’s the Cl- bit that does all the work. The Mg, K and Na ions are just innocent bystanders. Na is the most innocent, K+ ions are an algae nutrient and MG ions substantially add to total hardness along with Ca ions. A good quality mag salt is only 98%pure, poor quality brands are 95%, regular pool salts are 99.8% pure. Regular pool salts are evaporated sea salt that is collected when the water is clean and clear, Mag salts are harvested from inland brine lakes that are subjected the runoff from the surrounding land and/or human activity (stormwater and sewers etc.).

Unfortunately I cant see how you can follow TFP within those warrantee ranges. But it would very difficult to keep within those ranges anyway. Especially when you consider that the industry standard ranges assume a regular shock treatment which would immediately void your warrantee anyway.

I have never read a single article that gives a logical, chemistry based, reason why a pH above 7.5 could damage a FG pool. There must be 100’s of 1000s + of FG boats that are out in sea water with a pH of 8.3.

 

[FGPP79]

Potassium and magnesium chloride will be equally corrosive … it’s the chloride ion (Cl-) that causes enhanced corrosion (crevice and pitting corrosion), not the cation. Either way, pH has the biggest influence on metal corrosion and so if you keep the water properly balanced then there’s nothing to be worried about. Salt water pools are “brackish” at best, not seawater.

Thanks Joyful noise. it seems obvious in hindsight now that you mentioned the cloride anion doing the work. I’ll put that concern to rest now.

 

[FGPP79]

30-50ppm is quite standard for CyA, industry standard that is. Although the dichlor and trichlor manufacturers would like that raised to 200ppm+. 1-3ppm FC is a common industry range although 1-4ppm is also used. The industry treats CyA and FC as independent values which is wrong when you understand the chemistry which they (the industry) should. I keep my FC at 10% of my CyA.

30-31C through a VIC summer won’t be uncommon but remember there are a lot of heated pools, both FG and concrete.

There is a lot of fancy advertising in the pool industry. When it comes to salt it’s the Cl- bit that does all the work. The Mg, K and Na ions are just innocent bystanders. Na is the most innocent, K+ ions are an algae nutrient and MG ions substantially add to total hardness along with Ca ions. A good quality mag salt is only 98%pure, poor quality brands are 95%, regular pool salts are 99.8% pure. Regular pool salts are evaporated sea salt that is collected when the water is clean and clear, Mag salts are harvested from inland brine lakes that are subjected the runoff from the surrounding land and/or human activity (stormwater and sewers etc.).

Unfortunately I cant see how you can follow TFP within those warrantee ranges. But it would very difficult to keep within those ranges anyway. Especially when you consider that the industry standard ranges assume a regular shock treatment which would immediately void your warrantee anyway.

I have never read a single article that gives a logical, chemistry based, reason why a pH above 7.5 could damage a FG pool. There must be 100’s of 1000s + of FG boats that are out in sea water with a pH of 8.3.

I’ll have to pin Joyful Noise and your post on the sofium, magnesium and potassium comparison. I’ll undoubtedly forget and ask myself the same question in a few months! great analogy with fibreglass boats too.

The most controversial choice I’m thinking of making is the colour. Dark grey / black. clearly a subjective topic, but from an aesthetic and landscape design perspective, it’s definitely the way to go in my particular case. The aim is to make it as much of a reflection pool as is possible in a swimmable plunge pool (5.2 x 3.2m, 1.65m deep). Based on Joyful Noises post on the inevitability of gelcoat oxidation over time, this will be a big gamble over the long term. I think it might be an informed risk I’m willing to take, but not sure yet. Getting some cold feet…

 

[AUSpool]

A dark colour with a bit of oxidation would look good I think. The dark pools are definitely a little warmer.

When it comes to equipment choice don‘t bother with ozone or UV if offered. ORP is pretty much useless if you use CyA. pH control can be handy but I couldn’t find one that would allow a set point higher then 7.6. I liked the idea of the low salt chlorinators but was worried about their potential longevity.

 

[Newdude]

it would very difficult to keep within those ranges anyway. Especially when you consider that the industry standard ranges assume a regular shock treatment which would immediately void your warrantee anyway

Ain't that some ......... 'stuff' ?

Here....... do what we tell you, or else.

Ahhhhhhh, ya shouldn't have done that mate. You're on your own now.

 

[AUSpool]

Ain't that some ......... 'stuff' ?

Here....... do what we tell you, or else.

Ahhhhhhh, ya shouldn't have done that mate. You're on your own now.

I know right.

You need to go into a shop and get your water professionally tested by a kid on school break.

And then there’s that wall of potions…
A bottle of this and a bag of that, and we‘ll see you again next week…

 

[FGPP79]

A dark colour with a bit of oxidation would look good I think. The dark pools are definitely a little warmer.

When it comes to equipment choice don‘t bother with ozone or UV if offered. ORP is pretty much useless if you use CyA. pH control can be handy but I couldn’t find one that would allow a set point higher then 7.6. I liked the idea of the low salt chlorinators but was worried about their potential longevity.

Thanks AUSpool,

my toes are starting to warm a little bit. I’m probably just overthinking it. Nothing lasts forever and everything changes over time. I’m also starting to come to the same conclusion about ORP and pH control. if the calibration, maintenance and accuracy needs constant regular input, I think I’d rather just put my efforts into testing myself and get to know the pool and process first hand. I’m still pretty keen to give a low salt version a crack, but we’ll see. Thanks heaps for your input again.

 

[RookiePick]

I think the grey colours are really interesting - they give the water a "steely blue" look that is pretty attractive. I feel the style of the whole home and landscaping needs to be right to support that look though...it is quite bold.

I think the ORP setup just move the maintenance time to a different area and then you have an added layer of complexity to navigate if anything goes awry. I'm sure it can be implemented effectively but not sure it will be a time saver for pool management.

I think, having learned a bit more here, that automation is more about having control of pump speed, SWG output turning on/off and ancillaries like heaters or water features.

The chemistry seems easiest to keep straight by regular monitoring. Then you know it's right instead of hoping the automation is doing it correctly.

 

[AUSpool]

Thanks AUSpool,

my toes are starting to warm a little bit. I’m probably just overthinking it. Nothing lasts forever and everything changes over time. I’m also starting to come to the same conclusion about ORP and pH control. if the calibration, maintenance and accuracy needs constant regular input, I think I’d rather just put my efforts into testing myself and get to know the pool and process first hand. I’m still pretty keen to give a low salt version a crack, but we’ll see. Thanks heaps for your input again.

When choosing a pool color you start with what you want or like, as you’ve done and then compare matching shell colors with photos of finished pools accounting for the conditions like sunny, cloudy, morning or afternoon. A pool will look a lot different once the water is in. Our pool builder gave us pics of pebble finish samples with the matching finished pool. It’s not perfect but it’s really the best you can expect. I’m sure mine changed a bit when we put the salt in.

There is few low salt SWG‘s on the market, there’s one just down the road from me I’ve been meaning the check out. SWG need a brine solution, they are good at how wonderful it feels and all the extra placebo benefits but they never identify the challenges of using low salt brines or how they over come those challenges and the possible impacts on longevity or running costs etc.

I love a bit of automation but a lot of it is adapted from commercial operations where they have bigger budgets and are continually monitored. They know what can go wrong, how to fix it and how much it costs to fix. In comparison the domestic stuff is a simplified version thats installed and forgotten about until it all goes pear shaped which isn't covered in the glossy advertising.

Self testing with a good kit and then adjusting as required and only adding what you need is what TFP is all about and there will always be people here willing to lend a hand. Choices for a decent kit a bit limited in AUS, we either import a Taylor K2006C with some extras or get our kit from CCL, Clear Choice Labs – Simple. Accurate. Fast.

Either way, a speed stir is must and is well worth the investment.

 

[RookiePick]

Just further to this, I have zero faith my pH controller doses consistently.

It's a peristaltic pump and should move the exact same volume of HCl every revolution of the pump. I have dosed 360mL of MA through it several times now and the pump has operated for widely varying times and the same apparent rpm. It has run for anywhere between 15 seconds and "dear god will this thing ever stop pumping!?!?" with the same dosage request.

I dosed "400mL" Saturday and the acid pump ran for about 20 seconds. My pH shifted imperceptibly.

 

[Newdude]

To me, you have to go get the gallon of acid, pour it into the pump tank and then monitor the pump.

You might as well just pour the gallon of acid into the pool and monitor the pool.

I get it for the people who like their toys. Automate it and get your fiddle/tinker on. But for most of us, it's more trouble than it's worth. If I had to go get chlorine and load it into my SWG, I wouldn't have the SWG either.

 

[RookiePick]

To me, you have to go get the gallon of acid, pour it into the pump tank and then monitor the pump.

You might as well just pour the gallon of acid into the pool and monitor the pool.

I get it for the people who like their toys. Automate it and get your fiddle/tinker on. But for most of us, it's more trouble than it's worth. If I had to go get chlorine and load it into my SWG, I wouldn't have the SWG either.

...well I know that now

I also have 5 gallons-ish of MA sitting on my equipment pad with whatever vapours emanate from the drum in the midst of my hardware. Not sure I love that either.

My point in relation to this thread was along the lines that automating the chemistry has it's own challenges. Monitoring and dosing the pool directly is very straight forward and that is the way I would go if speccing out the equipment again and spend that money in more useful areas.

 

[AUSpool]

Just further to this, I have zero faith my pH controller doses consistently.

It's a peristaltic pump and should move the exact same volume of HCl every revolution of the pump. I have dosed 360mL of MA through it several times now and the pump has operated for widely varying times and the same apparent rpm. It has run for anywhere between 15 seconds and "dear god will this thing ever stop pumping!?!?" with the same dosage request.

I dosed "400mL" Saturday and the acid pump ran for about 20 seconds. My pH shifted imperceptibly.

It’s a good point and something @FGPP79 may like to now. I believe that is a Pool Controls pH controller that doesn’t use a pH probe? Instead it bases it’s dose volume on the SWG’s FC output believing that FC is the driving factor for pH rise which of cause it is not. Dissolved CO2 trying to equalize with atmospheric CO2 is the driving factor. If you increase TA you increase dissolved CO2 and increase the rate of pH rise. This links back to the high TA levels required in those warrantee ranges.

 

[AUSpool]

My point in relation to this thread was along the lines that automating the chemistry has it's own challenges. Monitoring and dosing the pool directly is very straight forward and that is the way I would go if speccing out the equipment again and spend that money in more useful areas.

Like an auto overflow and top up. Without one you can almost guarantee that if it’s about to overflow and you need to drain to waste it will be cold, raining, dark and blowing a gale.

 

[RookiePick]

It’s a good point and something @FGPP79 may like to now. I believe that is a Pool Controls pH controller that doesn’t use a pH probe? Instead it bases it’s dose volume on the SWG’s FC output believing that FC is the driving factor for pH rise which of cause it is not. Dissolved CO2 trying to equalize with atmospheric CO2 is the driving factor. If you increase TA you increase dissolved CO2 and increase the rate of pH rise. This links back to the high TA levels required in those warrantee ranges.

I have disabled the automatic dosing function, at least until I get a feel for what the pool wants to do...except for the one time I forgot to turn the doser back off after making it do a manual addition and my wife rang me in a flap about the strange and awful noise the pool pump was making (the peristaltic pump is quite noisy and an unusual "pulsing" sound) - oops!

It should be a pretty similar set up to the SWG in the end - get a handle on the acid demand and set the doser to provide roughly that rate, monitor regularly and adjust output as required. Should be fine but kinda superfluous.

 

[FGPP79]

Hey guys. Thanks heaps for the ongoing tips. I think I’m rapidly dialling in some direction here. Feeling much more confident in my choices now. Keep it simple, keep it informed. Skipping the ORP and pH control. Not fussed about needing low salt; keep it simple.

 

[FGPP79]

When choosing a pool color you start with what you want or like, as you’ve done and then compare matching shell colors with photos of finished pools accounting for the conditions like sunny, cloudy, morning or afternoon. A pool will look a lot different once the water is in. Our pool builder gave us pics of pebble finish samples with the matching finished pool. It’s not perfect but it’s really the best you can expect. I’m sure mine changed a bit when we put the salt in.

There is few low salt SWG‘s on the market, there’s one just down the road from me I’ve been meaning the check out. SWG need a brine solution, they are good at how wonderful it feels and all the extra placebo benefits but they never identify the challenges of using low salt brines or how they over come those challenges and the possible impacts on longevity or running costs etc.

I love a bit of automation but a lot of it is adapted from commercial operations where they have bigger budgets and are continually monitored. They know what can go wrong, how to fix it and how much it costs to fix. In comparison the domestic stuff is a simplified version thats installed and forgotten about until it all goes pear shaped which isn't covered in the glossy advertising.

Self testing with a good kit and then adjusting as required and only adding what you need is what TFP is all about and there will always be people here willing to lend a hand. Choices for a decent kit a bit limited in AUS, we either import a Taylor K2006C with some extras or get our kit from CCL, Clear Choice Labs – Simple. Accurate. Fast.

Either way, a speed stir is must and is well worth the investment.

Thanks for two suggestions. Just saved me a pile of time goi g down a Google rabbit hole.

 

[RookiePick]

I think the sales pitch on the low salt and minerals is so appealing because it sounds "softer" on the people swimming. We all remember times swimming in pools and feeling like it was a "harsh" experience - stingy eyes et al.

I suspect most of these experiences have been more to do with the water being out of balance than the method of chlorination.

 

[Newdude]

I suspect most of these experiences have been more to do with the water being out of balance than the method of chlorination.

*all.

Surely my friends who had pools for decades HAD to be pros. And the water park and the public pools had actual pros maintaining them.

Or so I thought.......