As I am filling my hydro res for the first time it occurs to me that I have no idea how much water is in the tank. This is important I think to myself. So the only thing I could come up with is to use a smaller tote and measure the contents by what the label says is the volume of the tote. I hope those numbers are volume and not area. I have a much closer water station but not one with a filter on it. I will remedy that soon enough, but out of curiosity, what's a good way to measure my water in terms of 10 to 30 gallons worth.

use empty gallon jugs to fill it the first time and keep track how many it takes. Then you can mark the inside of the res for your full water line and always know that it takes xx gallons to reach the line

i pre mix all my nutes in 5 gallon buckets.i do all my ph and tds corrections before it even makes it to the rez.so say u have a 20 gallon rez thats for 5 gallon buckets of nutrients u need to mix up.

75 liters thus far. I need to get a gauge or something and put it on the end of my hose. Either that or create a dip stick or something. What a pain in the butt that will be to make.

Dunno if you can weigh the res, but H20 is ~8.3 lbs/gal. Or:

I stuck a BBQ skewer thru a wine cork and made a "bobber." Drilled a small hole in the top of the res cover for the skewer to stick out and put marks on the skewer at .5 gal intervals. (A Wee Zard invention.)

I like that idea for sure. My tote is fairly big having space for 10 net pots. I think it will hold at least 35 gallons but I have no way of knowing. It was the largest one wal-mart was selling.

Get a 5 gal bucket, make a mark at whatever intervals you want, and when the res is full you will know how many gallons it contains. Marking out 5-10 gal intervals is always nice just so you can tell where your res is.

Just fill it to whatever level you want it at, and then measure the PPM's as you add your nutes. Or the gallon jug thing would work too.

if u want to be able 2 seee how full it is with out making a float,u can get 2 grommets 2 half inch 45 degree bends and a length of blue see through tubing.drill a hole at the bottom of the rez and one at the top,put your grommets and fittings into your drilled holes and slide the tube onto both 45's its water proof and will show u your rez level,just make your water level indicator on a side thats not in direct light.

THAT's IT! I was just telling my wife tonight that I have seen my brothers crew use a similar method when leveling the concrete during pool construction. They would take a bucket of water, insert a long flex rubber tube to create a level that they could then extend to any part of the pool to get the same exact level as the other side. I was trying to figure a way to implement that principle somehow. I just need to put a length of tube on the outside of the tote connected to the bottom of the toe.

However the more I resolve this issue the more I realize that it's a pointless measurement to take. Isn't it? I mean if like a previous poster said, if all I do is measure the new water then why do I care how much water is in the current reservoir.