I don't remember a post noting specific algae problems, (but, my memory sucks, and I didn't take the time to view your older posts) but algae is just a given in a new tank. It needs to burn itself out. While you want to keep it in check with water changes/gfo/manual removal, you are fighting a battle and it is just going to take a while to win, trying to rush it rarely helps. I don't see that you listed tank size or how long its been setup, but those would be useful in helping to advise on moving forward... In a tank under a year, I (personally) wouldn't be looking at chemical solutions (ultra algaex), just because I've seen enough posts noting that folks have killed bio filters with them, and they don't do much to treat the root cause regardless. I don't know if this added to your issues or not, I don't think there isn't a good way to know that. I agree with others though that something probably killed the bio-filter off at least partially, and once that starts, it can be a snowball effect. I also wouldn't rule out some reaction between the ultra algaex and the phos gaurd, but I don't know anything about that treatment, so it might be plenty safe.
The biggest thing I'd like to note about everything you said, and one of the things we've probably all done, is to make too many changes at once. Sometimes its just the logical thing too do, like adding the algae stuff at the same time as you brought the sump online, and trying to adjust salinity also. Its likely a lot of the time that you could have pulled all that off without a hitch, the problem is those 'other' times. You are left with too many culprits to determine the cause, and while the cause may not effect the fix, since more often than not we are left with water changes being our best/only solution, an understanding of what happened may help to determine if there are other possible routes, and at the very least give you a heads up as to what not to do next time.
You noted a couple of tangs. I'm not going to go 'tang police' on you, especially when I don't have any idea what size tank you have, but do want to note that they are heavy bio-load fish.. lots of waste. And they are also oxygen hogs, likely because of how actively they swim when healthy.. when they have problems, IMHO the first thing you want to do is anything you can to over oxygenate the water. (power head pointed at the surface, air stones, whatever you can think of) Anytime I see any issue with fish, I try to do that, regardless of them being tangs or not... Kind of like how they proactively with throw on oxygen mask on folks at the hospital, it may not be needed, but rarely is going to hurt anything.
It sounds like you may have calmed the storm for now, which is great. I'd continue with some extra water changes if it were my tank to continue to dilute whatever the problem might be, but on a smaller scale I think.. depends on the size of the tank... If the ammonia isn't under control, I wouldn't be afraid of a little amquel or prime, between water changes if necessary.
If you get some specifics posted about your current setup, folks may be able to advise more on the algae issues and help with getting that a little more under control once you've work through this...
The biggest thing I'd like to note about everything you said, and one of the things we've probably all done, is to make too many changes at once. Sometimes its just the logical thing too do, like adding the algae stuff at the same time as you brought the sump online, and trying to adjust salinity also. Its likely a lot of the time that you could have pulled all that off without a hitch, the problem is those 'other' times. You are left with too many culprits to determine the cause, and while the cause may not effect the fix, since more often than not we are left with water changes being our best/only solution, an understanding of what happened may help to determine if there are other possible routes, and at the very least give you a heads up as to what not to do next time.
You noted a couple of tangs. I'm not going to go 'tang police' on you, especially when I don't have any idea what size tank you have, but do want to note that they are heavy bio-load fish.. lots of waste. And they are also oxygen hogs, likely because of how actively they swim when healthy.. when they have problems, IMHO the first thing you want to do is anything you can to over oxygenate the water. (power head pointed at the surface, air stones, whatever you can think of) Anytime I see any issue with fish, I try to do that, regardless of them being tangs or not... Kind of like how they proactively with throw on oxygen mask on folks at the hospital, it may not be needed, but rarely is going to hurt anything.
It sounds like you may have calmed the storm for now, which is great. I'd continue with some extra water changes if it were my tank to continue to dilute whatever the problem might be, but on a smaller scale I think.. depends on the size of the tank... If the ammonia isn't under control, I wouldn't be afraid of a little amquel or prime, between water changes if necessary.
If you get some specifics posted about your current setup, folks may be able to advise more on the algae issues and help with getting that a little more under control once you've work through this...
