yup. 1 for 5 gallon. 1-2 in 10 gallon...2 in 18 gallon.

as far as how often you change using bigger rez...If you want change your solution less frequently. You can top off with water up to one full replacement of solution. Once you have replaced 100% of solution. Refresh with new batch.

i.e. if in 5 g bucket. once you add 5 gallons. you have to change.

if you have 10 gallon rez...then you can top-off 10 gallons of ph'd water.

I agree that 600 watt lights put out almost the same lumens as 1000 watt lamps, but the price is very close also...So alot of growers...myself included prefer to pay the little bit extra for the extra lumens.

I like the consideration of heat issue that racerx brought up. I use my old magnet ballast to enhance heat temps on the cooler winter nights.

As a matter of fact...You could heat your living space or a cooler room with the hot air you vent from grow space. Peace
latewood Reviewed by latewood on . Latewood's Legacy: GH 3-part and CalMag tutorial and discussion After experimenting for 2 years with Advanced Nutrients/additives... Botanicare Pure blend Pro/additives...and GH3-part/additives. I fond this formula works and yields the best; And leaves the roots healthy throughout grow. Goodluck This should answer a lot of question's you newb's have, and It should save you some money in the longrun. Since a lot of you get caught up in the Lucas Method. I found this to yield more. However if you have space limitations, just remove the Grow from Rating: 5