A couple of quick questions please?

[brian987]

So...I have decided to follow the advice of those who say I don't necessarily need to drain my pool in order to bring CYA and CH down...seems to be working quite well so far. But I am still feeling somewhat confused on a couple of issues.

1. I keep reading that when the FC levels are above 10, you can't always trust the pH test either. But because my CYA is still at 80, I am told to keep my FC levels around 11...no problem...but is that affecting my pH test results? I am also trying to keep that around 7.2 until I an get the TA lower...

2. CSI...I feel like I am supposed to be solving crime when I see that! Anyway...the numbers they say would be bad for plaster or for everyone...do I need to worry about that while I am getting the balance elsewhere? My plaster is only a year old and before I had it replaced, it was in such bad shape from many years of neglect from the previous owner...I just worry that this process is causing damage to my awesome, smooth, pretty plaster!'

My water is staying very clear...although it feels as if there is an almost residue like substance on my skin when I get out of the pool. No visible algae forming.

Here are my current test results:

FC 14.5
pH 7.2
TA 130
CH 600
CYA 80
CSI 0.19 -0.17

I am decent at the chemistry because I have done hair color for 30 years and much of the chemistry we are taught is the same...I spend my days deciding which hair care or color is acid, balancing the pH to 7.3-7.5, etc.

And that brings me to a quick side note: We use the term "Balancing" the chemicals too loosely. After all, one can "Balance" the chemicals to be acidic or alkaline if you should so desire. Balance technically doesn't imply taking the pH to any given standard...ie: Johnson's Baby Shampoo doesn't cause your baby to cry because it is "Balanced" to match the pH of tears. And that pH is very drying to the hair and skin over time. I apologize in advanced for being anal about terminology. It has been drilled into my head for so many years that if we don't clarify exactly what we mean, then you may just end up with Red hair instead of Blonde!!

 

[JasonLion]

For FC levels around 10 to 15 you can assume that the PH test reads between 0.1 and 0.2 higher than actual. That isn't exactly true, but it will be close enough for most uses.

Since your CH level is so high, keeping your PH low will work out fairly well. If CSI goes a little out of range for a day or three it isn't a problem, but you don't want it too far out of range for too long. How far is too far and how long is too long varies. Right now, your main risk is if the PH goes up you could have calcium scaling. Lowering TA will help make that less likely.

In a swimming pool context, balancing your levels means getting all of the levels collectively to a place where you won't have problems, typically getting your levels in range of the recommended levels. That isn't the same as the chemistry definition, though it is similar in some ways.

 

[257WbyMag]

So...I have decided to follow the advice of those who say I don't necessarily need to drain my pool in order to bring CYA and CH down...seems to be working quite well so far.

I'm not really sure where you heard that you don't need to drain water to bring your CH and CYA down, but aside from reverse osmosis, there is absolutely no other way that you will ever bring these two values down in your pool. To suggest that anything other than changing out water or getting RO performed to accomplish this would be completely incorrect.

Now you can live with higher CH and CYA values assuming that you watch your FC and CSI. It sounds like you are doing this as well.

 

[brian987]

Actually, I was given the advice to drain or not drain...not draining was advised because I live in a town that averages at or just below 100 every day until at least the beginning of September. My pool get almost no shade...only early AM and pretty late PM because of the fence around my yard. So I get a few inches of evaporation, at least, each week. Then, when it finally does decide to break the drought, it does it like it is the last time we are gonna allow rain on our town ever! Point being, I understand removing water is the only wat to adjust these levels, but since I am in no immediate danger and I am keeping my FC about 11...I should be close to what we consider normal levels by the end of summer.

 

[257WbyMag]

We're neighbors.

Alrighty then. You do realize though that the water that evaporates from your pool doesn't take any calcium or CYA with it when it does though? You can replace evaporated water but the CYA level will be the same as it was before. The calcium, depending on how much you have in your fill water, can stay the same or rise from this. With evaporation, the only thing that leaves your pool is water. So the only way that your CH and CYA can come down to "normal levels" is by your sending water to the drain or from a significant amount of splash out.

 

[brian987]

No, I haven't heard that before. I like that on this forum we have room for many differing viewpoints, but is that statement from science or experience? I think that may need to be clarified when others are giving advice. I have heard an almost equal voice for both sides of this discussion from people on this website. Now I am getting confused as to which route I should take. Can anyone offer some advice about who I should listen to when it comes to chemistry of my pool. I don't want to sound like I am putting anyone down, but this is starting to feel a bit like the pool store guys and the pool maintenance guys all having such opposite advice that I get to a point where I just don't know if anyone really knows how to take care of a pool. Help!

 

[257WbyMag]

Happy to explain.

To illustrate what happens when water evaporates, I like to use the "boiling pot of water" example. Have you ever put a pot of water to boil on the stove, forgotten about it, and returned to find that the water was gone and you are left with white and crusty deposits on the sides and bottom of your pan? These are the minerals that are found in your tap water. When water evaporates, only the H₂O can go. The minerals or other dissolved solid things in the water cannot evaporate into the air. The CYA isn't going to evaporate. Any metals that you have in the water (Na, Ca, Fe, etc.) cannot evaporate. Only the pure water can go. So even if you left your pool alone for months and let all but about a foot of water evaporate into the atmosphere, you would still have the same amount of CYA and calcium (by weight) sitting in that foot of water that you had in the pool when it was full.

Does this all make sense?

 

[frustratedpoolmom]

Its science.

I guess I'm not clear on what your specific concern is? Your CH level is high. Your CYA level is high, and you have no SWG.

Can you maintain a sanitary pool with CYA of 80? Yes, it's doable, its just more complicated, especially if an organic problem develops. Will the level slowly come down over time? Yes it will slowly come down if you don't add it on a regular basis.

Depending on your fill water, your CH level is more complex, because of the surface of your pool. It would take significant water replacement to get your CH to "normal" levels. Can you manage with the high CH? Possibly, but you do risk scale so monitoring PH and TA become extra important.

I'm not sure what the "residue" you are feeling on your skin - there could be a number of factors at play.

So if your issue was just high CYA and you didn't want to drain, that I could understand and we could help you manage things where they are at, it's been done before.

Coupled with the high CH it makes things slightly more complicated, but again, it's always the pool owners decision in the end, as you are the one who has to deal with the ramifications of that decision. We can only offer you the information to help make an informed decision.

In the end, I'm not sure I helped. LOL

 

[brian987]

Thanks. That makes total sense. But just curious, why are people here telling others to just not worry about removing water? Am I maybe misunderstanding and they are just saying that it is OK to keep higher levels as long as you keep the FC levels up there as well? Because won't all the higher levels, besides being more expensive, eventually begin to take a toll on the plaster and/or equipment? I guess I am asking...according to the suggested goals here, both my CH and CYA are close to double the recommended levels. If that level isn't gonna change unless I replace water, then what could the arguments for keeping that much higher of a level be? I can understand if it were just slightly high...but we are talking double.

I sincerely am not attempting to start a battle here. This just seems very confusing to the inexperienced person to offer such conflicting advice.

 

[brian987]

OK...the argument for draining is making much more sense to me. Especially since my plaster is still only a year old. That kind of cash isn't just hanging out on the side of my pool and I want to be sure to protect it. And even it were just about cost of replacement water, I think it is well worth that expense to make my life simpler. The older I get, that has become about the most important aspect for my life. KISS. Thanks for explaining it in a way that gets through to my "right" brain. Logic sometimes takes a backseat to art for us, but simplifying my life is something I can relate with.

 

[257WbyMag]

The argument for keeping water with higher levels of those things is for conservation or monetary purposes. In some areas, there are so many restrictions on water use that a full change-out of pool water is not legal, not practical, or just too expensive. In the arid parts of the desert southwest, high CH is common. These folks must learn to contend with these high levels because changing out water is just not in the cards when your fill water CH is already 400 ppm. So these folks have to get creative to keep from getting scaling by making chemistry adjustments based upon the CSI. Likewise, those with high CYA levels who are in the same water situation may just find that they have to run a higher FC.

When levels of CH and CYA are too high, the treatment is always going to be changing out water. This is just not as easy for some as it is for others.

 

[frustratedpoolmom]

I know what you mean. When I first found TFP in 2007 I was very overwhelmed by it all at first. It took a while for it to slowly sink in.

For the most part contradictory recommendations come because they don't understand the chemistry or the science behind it, or they haven't taken the time to learn or understand.

In hot sunny locations like AZ for example one might find better results with a CYA of 70-80 than a level of 40. High CH on the other hand there would be no reason to maintain a higher level - too much risk.

No you don't run a risk of damaging your pool/equipment by maintaining the CYA of 80 and the corresponding FC as it's all relative. High CH on the other hand you pose a risk to it simply from scale.

 

[DWSPool]

I can vouch for what 257WbyMag stated about water loss vs. chemical loss - this is based on my 30 years professional experience in water resource issues and water chemistry.

If you lose pool water by splash out, leakage, pump-out (backwashing the filter), the chemicals go with the water. And when you replace with lower-CH, no-CYA water (ie, tap water), or you get lots of rain water, the concentrations of CH and CYA will drop. (In some instances, your water supply (tap water, for example) may have higher CH than your pool water, in which case your CH will increase by adding tap water, but that's another story).

If you lose water by evaporation, the water leaves, but the CH and CYA remain and the concentrations actually will rise until you replace with fresh water and the concentrations return to their original level.

I found this site about 2 months ago. Generally, I have found the advice throughout this forum to be highly consistent and accurate - it may seem there is conflicting advice sometimes until you become familiar with all the terms, acronyms, and methods. Sometimes, it's simply a communications problem (on both ends of the conversation!). But, I believe if you stick with this forum, you will get everything sorted out. Hang in there.

 

[Steve456]

The advise you are given may differ by degree since members of TFP live in different areas and have had different experiences. Most agree with the recommended levels presented here: pool-school/recommended_levels

It is more important that you understand the reasoning that goes into why these levels are recommended than adherence to the absolute numbers. If you are willing to maintain the higher FC levels required with a high CYA then you can be successful. If you understand that a high calcium level can lead to scaling and you watch your pH and CSI index you can be successful. The recommendation to replenish your water is based on collective experience that pool owners get busy, let the chemistry drift, and start encountering problems because they have a low margin for error.

I watch the chemistry of my pool carefully but accept some out of recommended values. My calcium is slight low so I have adjusted my pH and monitor it carefully. My alkalinity is slightly high because my fill water is high in alkalinity. I know how to add acid to lower the alkalinity but I test the water and will lower the alkalinity if it gets too high. I am a little lazy. My CYA is close to your CYA level but it is in the recommended range for a SWG pool. When we purchased our house our pool calcium level was much higher than 600; we kept the pH a little low and did not drain the pool until the next year. No problems.

You want to pick an appropriate time to replenish the pool water. If you lower your pool water and it rains and you have a high water table your pool can be damaged.

Read the Pool School. To simplify pool maintenance follow the BBB method, test your water yourself, and maintain the pool water chemistry within the recommended levels.

 

[Mona]

If you lose pool water by splash out, leakage, pump-out (backwashing the filter), the chemicals go with the water. And when you replace with lower-CH, no-CYA water (ie, tap water), or you get lots of rain water, the concentrations of CH and CYA will drop. (In some instances, your water supply (tap water, for example) may have higher CH than your pool water, in which case your CH will increase by adding tap water, but that's another story).

Since the biggest issue is getting your CH lower which is the biggest threat, have you tested your fill water?

 

[brian987]

Actually, yes...I don't remember the exact number but it was low. I think it was a little higher than 100. So that is good to go, but that part I already knew from experience last year when the plaster was done and I had to refill completely. I have been monitoring my water daily now and am keeping the pH close to 7.0 and FC at minimum of 10-11. Since we spent our vacation money on plaster, I don't have to worry about not being here to take care of it personally. Thanks to everyone for your patience. My artistic brain takes a little longer to comprehend the mathematical world! BTW, the Iphone App for the calculator is very convenient. And I would like to say how awesome it is that you guys respond to these questions so quickly,

 

[dfenrick]

Happy to explain.

To illustrate what happens when water evaporates, I like to use the "boiling pot of water" example. Have you ever put a pot of water to boil on the stove, forgotten about it, and returned to find that the water was gone and you are left with white and crusty deposits on the sides and bottom of your pan? These are the minerals that are found in your tap water. When water evaporates, only the H₂O can go. The minerals or other dissolved solid things in the water cannot evaporate into the air. The CYA isn't going to evaporate. Any metals that you have in the water (Na, Ca, Fe, etc.) cannot evaporate. Only the pure water can go. So even if you left your pool alone for months and let all but about a foot of water evaporate into the atmosphere, you would still have the same amount of CYA and calcium (by weight) sitting in that foot of water that you had in the pool when it was full.

Does this all make sense?

Not to be a jackass, but while you are correct about the CYA not evaporating, it's not true that ONLY H₂O leaves naturally. Dissolved gasses will off-gas. Chlorine leaves (or more correctly breaks down) over time. Other trace volatiles (if any) will evaporate with, or before the water goes. And of course there are the cases where during/after a winter shut down, people have come back to a pool with little or no CYA due to it being consumed by reacting with other 'stuff' in the pool.

I guess what I'm trying to say is that EVENTUALLY, the CYA level will come down, but it will take a long time and it not quite as simple as Pennies and Nails don't evaporate. (At least not at our regular pool temperatures. )

 

[257WbyMag]

Happy to explain.

To illustrate what happens when water evaporates, I like to use the "boiling pot of water" example. Have you ever put a pot of water to boil on the stove, forgotten about it, and returned to find that the water was gone and you are left with white and crusty deposits on the sides and bottom of your pan? These are the minerals that are found in your tap water. When water evaporates, only the H₂O can go. The minerals or other dissolved solid things in the water cannot evaporate into the air. The CYA isn't going to evaporate. Any metals that you have in the water (Na, Ca, Fe, etc.) cannot evaporate. Only the pure water can go. So even if you left your pool alone for months and let all but about a foot of water evaporate into the atmosphere, you would still have the same amount of CYA and calcium (by weight) sitting in that foot of water that you had in the pool when it was full.

Does this all make sense?

Not to be a jackass, but while you are correct about the CYA not evaporating, it's not true that ONLY H₂O leaves naturally. Dissolved gasses will off-gas. Chlorine leaves (or more correctly breaks down) over time. Other trace volatiles (if any) will evaporate with, or before the water goes. And of course there are the cases where during/after a winter shut down, people have come back to a pool with little or no CYA due to it being consumed by reacting with other 'stuff' in the pool.

I guess what I'm trying to say is that EVENTUALLY, the CYA level will come down, but it will take a long time and it not quite as simple as Pennies and Nails don't evaporate. (At least not at our regular pool temperatures. )

No problem, but we weren't talking about dissolved gasses. Rather, we were talking about CYA and CH. Listing each and every substance and how it responds in this situation is beyond the scope of this forum.

Calcium is a metal and therefore, stays behind. The only time that CYA is "consumed" is if the pool water environment is deficient in sanitizer and because we don't advocate for folks to allow their pool to go green in the hopes of inviting an ammonia problem so that their CYA can be lowered, we instead tell them how to live with a high CYA or advise them to just drain the pool to lower it.

 

[brian987]

I think I am getting close

So, after a couple of drain and refill afternoons, my water is currently testing as follows.

FC 5
pH 7.5
TA 80
CH 430
CYA 70
Temp 86

So, I added bleach to get the FC levels to 8.0. Is that high enough with CYA of 70? Is there anything else I need to worry about for now? I plan on at least 1 or 2 more drains in order to get the CH and CYA down to normal.

 

[duraleigh]

Re: I think I am getting close

Hey, Brian,

Do you have an earlier post with other (more) info?

If so, it helps if you delete this one and put it in the older thread so we can all follow your whole "story"