Hello, TFP members. I'm another pool store worker, and although you guys like to talk down about us, I was wondering if I could ask for some help. However, my problem is a little different than what's been posted here already. Let me warn right now the problem might require advanced chemistry. I hope I'm posting this in the right place. I apologize if I haven't.
Here's the story: my boss is currently working on a vanishing edge pool on a service call. The pool itself, which has plaster walls, is ~18000 gallons with a 2000-3000 gal. basin at the bottom of the waterfall. The water gets recirculated, not through a filter, into a spill over spa of ~600 gal. The pool has an ozonator, a Delozone TrioPure to be exact. It recommends that at least 3500 ppm of salt is kept in the water.
Because of the whole waterfall system, it is estimated that around 100 gallons of water is lost a day. So, there is an auto refill system to add fresh spring water to the pool when needed. Let's assume that whatever lost is gained in a course of a day.
Now here's the problem I'm stuck with: because of the whole water loss situation, no matter how miniscule the loss, my boss wants me to model how each chemical level changes with time (keep in mind this is only a summer job for me and this is just a mom and pop pool store). This includes calcium hardness, salt concentrations, stabilizers, chlorine, total alkalinity, and (most unfortunate of all) pH. Everything. He wants this done so he can ensure the clients keep not only the chemicals where they need to be, but they have the right settings on the ozonator.
Here are the current levels from tests I did on the water today (done with a Taylor 2005 kit):
FC and TC: 0
pH: >8.0 (It was busy in the store today and because this was my last test, I didn't have time to do an acid demand test)
CYA: <30 (It's low)
Salt: 700 ppm
Some of these will be easy. Some of my assumptions include the spring water not including calcium hardness (probably a bad one) and cyanuric acid, so it's just simple solution chemistry to figure it out. If they are bad assumptions, these were only starting points.
The other chemical levels, not so much. Chlorine is being generated by the electrolysis of the salt in the water, which is being done at an unknown rate. However, the hypochlorous acid being formed can be degraded in the sunlight. Even worse, these rates change with the presence of CYA, some of which is being lost everyday. There's also the chlorine being lost through the waterfall. All of that has to be considered.
Salt wouldn't be so bad except it being electrolyzed and lost at the same time. I'm not familiar with the electrolysis rates of the ozonators, and no matter how hard I look I can't find any information on it. So, I have no idea how fast the salt is being degraded.
Alkalinity and pH are going to be the very, very hard ones. Already, there is major aeration, contributing to a possible climbing pH. Without knowing the appropriate reaction kinetics, I don't know how fast this climb takes place. I know baking soda and soda ash come together to make a buffer, but I'm not very familiar with the specific equilibrium chemistry you can use to determine how something specific is affected for that system. Also, there is the problem of the incoming water being of a different alkalinity and pH than the pool water. Plus, the pool's pH is going to need to come down, and how is the chemical ultimately used for that specifically going to affect the buffer, let alone the pH and alkalinity? This is probably going to be way too complicated to figure out by hand, but no one is taking "I'll try to figure it out" or "This is way too hard" as answers. So, I'm stuck.
Basically, where do I start to begin figuring this out? Where should the chemical levels be in a pool like this? I'm adept in chemistry, so if anyone can help me out, use all the jargon and mathematics you want. If this is too hard of a question on this board, is there anywhere else I can go? Unfortunately, in my situation, it's not good enough to simply say, "set up and check and adjust the chemical levels frequently", so I don't want to be pressuring or anything, but I need at least a ballpark model to go back with.
If anyone can help me, I greatly appreciate your help. Thank you.