Cleaning my reservoir towards the end of flowering...please help!

Hi all,

Been a long time lurker of this site--thanks to all of y'all who make this site what it is!

I have a very nice DWC closet grow that I've fine tuned over 4-5 grows. It's all CFL and in this last grow, I took the least active approach possible, and it's been really successful. I used to try LST and SCROG, but it was just such a pain in such a small space (I'm growing in a 16" x 24" rubbermaid, which is the largest I could fit in the corner of my closet). I now have 3 strains growing right next to each other, all with the same photoperiod and approximate size. Big Buddha Cheese, Dinafem White Widow, and Samsara Sweet Black Angel.

This is the greenest grow I've done to date, making it all the way to 5 weeks of flowering without a single discolored leaf. All I've done is raise the lights as the plant grows and some supercropping to even out the canopy.

I've used only FloraNova, grow then bloom. I've got a $14 TDS meter and the $15 GH PH kit from amazon, which I check about once a week when I add more water.


I'm now at week 8 since switching to 12/12 and I think I've got 2-4 weeks left (gonna let some go full amber for the knockout!). At this point the upper leaves have started getting some significant discoloration and brown spotting which I've attributed to less attention to PH in the last few weeks due to a crazy work schedule and potential potassium, cal/mag lockout due to residue left in the reservoir which I've never cleaned.


So, to the question:

I just today bought a matching rubbermaid reservoir and had a hell of a time switching out the old for the new. My buds were keeling over left and right and the roots had pretty much consumed the air stones, so it was really hard to make the transfer as the air tubes had been put through the side of the old reservoir.

a) Is it necessary that I remove and clean the reservoir during the grow process? I have a small water pump so I can empty the reservoir to about 1/2 an inch of water, then put in new clean water, but there's still a lot of residue on the bottom. OR do I just need to really pay attention to PPMs and PH?

b) If I do need to remove the reservoir and clean it, can anyone suggest an easier way to do it with my setup?





Thanks to any who can offer some help! Got some monster buds that I want to keep healthy!

Unless you get some bad stuff in there (rot, mold , algae) then There is no need to clean it before your done. If you do and need to clean it then you really do need to get the plants out of there to do it correctly (hot water and bleach).

I run multiple 50gal res'a and when they go into flower room they don't come out for 9 weeks. I use the pump to empty and spray water in to rinse it then refill with water and nutes. It gets a bleach bath when it is harvested.

Okay, so I think I just got paranoid because this is my best looking crop yet, and I slacked off for a few weeks. Since I adjusted PH, I've seen no additional spread of the discoloration or spotting. Thanks guys!

I'm sort of in the same boat. I have two dwc bubble buckets for two plants. This run I got a ppm meter, so I've been measuring my ppms and adding only what I need. I changed my res at 5 weeks when I flipped. But I'm not changing it anymore. The plants are just too big to negotiate the switch a res change requires. However, I'm not having any problems either -- no slime or algae, water is clear except for nutes tinge, nothing smells funky and roots are white, minus the nutes tinge. And the plants are ridiculously healthy.

Unless something dramatic happens, I'm not changing anything.

kryptoniteglo said:

I'm sort of in the same boat. I have two dwc bubble buckets for two plants. This run I got a ppm meter, so I've been measuring my ppms and adding only what I need. I changed my res at 5 weeks when I flipped. But I'm not changing it anymore. The plants are just too big to negotiate the switch a res change requires. However, I'm not having any problems either -- no slime or algae, water is clear except for nutes tinge, nothing smells funky and roots are white, minus the nutes tinge. And the plants are ridiculously healthy.

Unless something dramatic happens, I'm not changing anything.

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thats why after my very first dwc grow i switched to rdwc when i flipped to flower..no way in hell was i going to lift that plant out of the bucket every morning to check my readings and add water/nutes..just wasnt going to happen.

dtischerd said:

thats why after my very first dwc grow i switched to rdwc when i flipped to flower..no way in hell was i going to lift that plant out of the bucket every morning to check my readings and add water/nutes..just wasnt going to happen.

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The checking readings and adding water/nutes is okay for me. I just lift the lid and slide it over a few inches. It's when I have to try to change the whole res by lifting the lid and roots and moving them to another bucket -- my plants are so big and heavy, and my space a little tight, that I can't pick a plant up and put it in the new bucket without potentially damaging some of the stalks/flowers or the plant next to it.

I've been thinking there probably is a better way, but I don't want to invest any more $$ in this right now. These are small, two-plant grows, and I've probably spent close to $1200 on everything -- tent, equipment, meters, nutes, seeds, etc. I need a few grows that are cheap before I can think about changing my system.

I use only 2" netpots and collars for all of my grow and I have an extra hole in the lid with an extra pot I can just pop out and then stick probe in bucket.

You could also just slide the lid over and use a wet-vac or water pump to suck out all the old nute water, then just dump your fresh batch in. just put an old sock or stocking over the end to keep from sucking up and damaging the roots. Even a bilge pump or siphon would work on the cheap if you don't have a wet vac or pump, but I bet if you check Craigslist you could find a wet-vac for $20 or less rather quickly.

I have this battery powered pump for kerosene that comes in handy for buckets and small totes. About $12 at Walmart.

superstoner1 said:

I have this battery powered pump for kerosene that comes in handy for buckets and small totes. About $12 at Walmart.

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Twenty dollar bucket heads at Lowes or Homedepot is where it's at... turn any 3.5-5 gallon bucket to wet vac... just be cautious of the roots when sucking it all up. Takes under a minute to suck dry a 5 gallon bucket.

Best twenty you will ever spend.