Def normal to have to add water -- lots of evap from low humidity --10% not unusual. Not sure how to answer your other question except generally all the beds will eventually cycle together, occasionally, so your sump tank and FT need to be able to handle that volume without going dry.
Bell syphons need to be adjusted occasionally due to various factors as your system ages.
Deborah, I have 35 1/2 barrel beds that operate on their own timing. I have found that all I have to do is look into the siphons each day to check the water levels. If the water is somewhere in between the top and bottom of the drain, it tells me it's working correctly. If the water is at the top or bottom, I watch for a few seconds to make sure its working, and only adjust if it's not right. The only time water level in the tanks has been an issue is if the main pump has been off. (As when I'm cleaning it)That causes the beds that are in the draining process to fill at the same time when the pump is back on. Then the next time, there are too many beds emptying at the same time which can overwhelm the sump. By only adjusting water fill in beds that are "stuck", The beds are draining very randomly which keeps the water levels in the tanks at a consistent level.
Also, as long as your beds drain quickly, that pulls the oxygen down to the roots which makes up for the beds filling slowly.
Thanks Cindi, Brent and Paul,
Looking into the iPhone is how I have been monitoring, didn't realize I should have them on a pattern.
Mostly concerned that plants in slow to fill bed are drowning.
I don't think it matters how long it takes to fill your bed as long as the siphon works and your FT cycles at least once per hour. The simplest way to address multiple GBs is with a large enough sump to eliminate any problems.
my research suggests that 15 min fill/drain cycles for 10 inch water level media/rock beds is the target to achieve optimum nutrient/oxygen ratios.
What is the majic size and distance from pipe to bell on a siphon to work right? i't been a practice of stubornness trying to get it to be consistant.
I use a 3/4 inch stand pipe with a 1 inch expansion adapter on top with a 1/4 inch v notch cut into the lip. its abouit 1 1/2 inches from the top of the bell. the bell pipe is 2 inch. all surrounded by 6 inch pipe with horizontal slats ax water inlet to the bell area