My water seems to be evaporating rather fast

Uhm, I dont know if I am doing something wrong or if this is just how it goes? The water in my resivoir keeps going down like a lot after its been a couple or a few days. I dont have a lid on my resivoir, is this why? Or is this just normal? Thanks.

Most likely its the plants that are using the water, A lid should always be used, especially to keep dust and dirt from getting into the works.

Thanks a lot, good tip. I just have the plants in a thing right above the resivoir and it just goes out the hole in the bottom right back to the resivoir. I could just cut a couple holes in the lid though where the drain is at and it would only be like 5 percent open lid then. Thanks a lot bud.

Yeah a ebb and flow arrangement is what you have. I normally need to replace 3 gallons a day in my Res(22 gallon) to keep up with what the plants use.

Wow I had no idea they took so much water! How good to know, I appreciate it. I just got it set up on drip system with perlite in the 5 and a half inch pots sitting in this like 2 foot by 6 inch planter and all the water just runs through the perlite down to the planter and out the hole in the planter and just like a water fall back into the resivoir. It is noisy but I really love the noise, it relaxes me lol its like those atmosphere cds people buy to relax and set the environment.

20 gal here and yes i have to fill mine every few days, and yes keep that lid on.
I have another 20 gal box for my soil. works well