There is a topping off schedule with the 3 part GH nutes that many use and use it with other nutes, but I can't remember it all the way. It is something like this, you top off with half strength nutes untill you have added back the amount of the res, so in your case, you would top off enough times to equal the original 50 gallons and then refill the system. Some times this takes a couple weeks or more. What kind of nutes are you using??
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