4th dimension? Sounds interesting.
You should start getting a bit more foamy right before your completely empty. Your wand should start feeling 3.7 ounces lighter. All suttle signs but you pick right up on it at exactly your 10,000th wash.
I havent washed quite 11,000.....but I CAN eat things that would make a billy goat puke.
Theres really no problem drawing air through your down streamer, we do it all the time. You can put a 1/4 valve on your chem line to stop flow, but we just pull the line out of the tank and rinse.
It's either or....... really.
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