Depends on how fast you can take this all in...Read this first, it's something I wrote for new growers at another site.
Rez management
When we talk about rez management we are talking about when to add water to your rez, when to add more nutrients and when to dump it all out and start over again. Every day your water level will drop due to evaporation and the plants drinking it up. Everyday you should add the same amount of water, which has dropped so that you keep it at a constant volume. You should take notes on how much you add back every day. If your using a 50-liter rez and every day it drops 5 liters, then you must add 5 liters back. After 10 days you will reach 100% addback, meaning that you will have added the same amount of water, which you started with. Here are 3 strategies that you can use to manage your rez
- 1. Add plain water + dump at 100% addback; this is the easiest method and is a good place to start for beginners. You add back plain tap water and once you reach the amount you started with you drain your rez completely and mix a new fresh rez and start again. You repeat this till the end of your grow. The plus side is you don’t need to measure your ppms with a pen and it’s easy to remember. The downside is that your plants are not getting a full meal most of the time.
2. 33% nutes + 100% addback: This method you are going to be replacing the food as well as the water with your daily toppings. Some smart people figured out long ago that the amount of food that the plants eat everyday usually equals 33% of the amount needed for the volume of water which is missing. So if you are adding back 1 gallon of water, instead of mixing Lucas formula at full strength for that one gallon, you only add 33% for that one gallon you add 2.64ml of micro (8ml * .33 = 2.64ml) and 5.28ml of bloom into the gallon of water and add it to your rez. Everyday you do the math for the amount you add back and once you reach 100% addback you drain the rez and start from scratch again.
3. PPM readings + 100% addback: Very similar as above, but instead of trusting that your plants have eaten 33% of the nutrients of the dropped water volume you use your ppm pen and find out how much they have actually eaten. It’s best to top of your rez first and let it sit for a while to get an accurate reading. Lucas formula is 953ppms 0.5 so if your reading is 800 ppm than you should be adding back 16% (800/953=0.84 or 16% less than 100%) of the total volume amount. So if you have a 20 gallon rez that would work out to 20*8ml*.16=52.8ml of micro and twice that for bloom. If this confuses you stick with the first options. Once again you drain your rez at the 100% addback point and start fresh.
A lot of growers don’t bother changing their rez during a grow. My advice is that a fresh rez is always better than one that’s been used and added back to over months, so I’d stick to dumping at the 100% addback.
