7:45 pm FC 30.5 since I'm supposed to target 27 or so and I have been losing only 1-2 FC level most nights, I'm not going to add more tonight.
One more question - I notice I am burning almost all the chlorine I use between 10:30 am and 2:30 pm. What would happen if I let the level drop to around 14-17 as it did today (not try to boost it high in the morning)? I'm afraid my husband is going to get upset with me having to buy too much chlorine sooner or later. Either that, or if there's anything else I can do to speed up getting it cleaned out, or if I can give him an idea of how long it's likely to take?
Its important to understand that chlorine will be consumed regularly, and will be consumed rapidly when there is algae growing in the pool. When you see the big drop during the day, it is for a couple of reasons. One, sunlight will break down chlorine. Two, algae thrive in sunlight. So during the day, it is normal to expect FC to drop more.
Under normal circumstances, you would need to regularly add chlorine to the pool just to maintain sufficient levels to prevent algae growth. With algae already growing, you need to not only maintain FC, but add enough surplus to fight the algae too.
One of the best analogies, is to think of it as a war. When the enemy, in this case algae, attacks with more force, you will experience more casualties (FC loss). At night the algae aren't working as hard because there is no sun, and the sun isn't fighting against you either. Your troops, the chlorine, continue to fight. During the day, you are fighting a much bigger army, and your advances will be smaller with more casualties. If you were to allow the FC to remain lower during the day, it would be like sending in less troops because you fear casualties. You might not lose as many troops, but you certainly won't win that battle either. Losing chlorine is part of the process, and can't really be avoided. If you get stingy about adding chlorine, you will create opportunities for algae to take the upper hand.
Don't let the cost of chlorine stand in your way of success. Yes it can get expensive, but it will only get more expensive if you try to hold back. If you hold back, the algae will take over again, and you will be starting all over. The chlorine you already put in the pool will have been wasted. Keep the FC levels at SLAM levels at all times. If you know you aren't going to be able to check them for a fairly long period of time, you might want to bring them a little bit higher.
It sounds like you are making good progress, so keep up the good work, and trust the SLAM process. It will work.