Why change water in hydro system?

dbz

Well-Known Member
"Many research scientists dump out nutrient solutions and refill at weekly intervals. Some authors have recommended automated measurement and control of individual nutrients in solution as essential to nutrient control. However, two decades of research in hydroponics has shown us that dumping and replacing solution is unnecessary. Monitoring ions in solution at frequent intervals is extremely expensive and not always necessary"
bruce bugbee - literally from the first paragraph of the paper

if u wanted to follow the bugbees methodology from this paper the only facilities you would need is an excell spreadsheet.

im flabbergasted that u would put forth an answer without even looking at the article posted. cmon man
I can't believe you don't understand not ALWAYS necessary. Should be easy for someone so unbelievably versed in the literature. Of course it isn't always necessary when you have experience with plants along those phenos or clones or such and already have done all of the monitoring which is extremely expensive. Since you like using bold so much. Hey though, don't listen to the people who grow at home, and maybe it will work for you without any changeup for different strains and phenos for a couple grows. People here tend to be invested in making 10/10 grows work not 7/10 or 5/10. Dr. Bugbee is brilliant, and a worthy resource, but to act like people do this for no reason is just your ignorance. Just to make it a little simpler for you, not always necessary means it sometimes is. Many large grows re-use, some smaller growers do with some luck. Most of the commercials that do are getting regular laboratory testing. We don't have the luxury of having already tested many strains and phenos with expensive lab equipment or if something seems off with our staple additions and re-additions then we can do extremely expensive testing. Once again stop asking questions when you already know the answer that you want. Good luck growing.
 

A e o n

Well-Known Member
could u have pulled it off from visual cues alone?

can i ask what u used from PH down.
also assuming u were growing cannabis i would be curious about roughly where u wanted to be total ec wise?
thanks

great post btw
Its extremely difficult/impossible to do it visually, alone. Nutrient deficiencies don't show up in the leaf until 12-72hour after it already has occurred, so if only using visual you will be behind the curve and never in optimal growth. With that said a master who has experience with the growth environment, strains, etc could do it through trial+error and Master Grower 6th sense.

Phosphoric Acid usually, but same principle as nutrients is applied to PH up or down material, using lab test results, since they also add elemental PPM.
Part of the greenhouse was salad greens and the other was tomatoes. EC vary greatly depending upon environment, and in a single 4 acre greenhouse, very different than indoor. But much higher than usual if reusing nutrient solution. A few grows back I tried recirc in drip coco instead of DTW and used the solution for about 1.5 months without lab results. And that was with a undersized res (about 1/2 of what is low end of recommendation), with big res could go whole grow cycle probably. Had some deficiencies but it was fairly minor;ended up with good product. With lettuce you cannot have any deficiencies or its likely a crop loss. Always keep the res fresh as stated and ideally oversize it if going recirc.
 
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JonCreighton

Well-Known Member
I can't believe you don't understand not ALWAYS necessary. Should be easy for someone so unbelievably versed in the literature. Of course it isn't always necessary when you have experience with plants along those phenos or clones or such and already have done all of the monitoring which is extremely expensive. Since you like using bold so much. Hey though, don't listen to the people who grow at home, and maybe it will work for you without any changeup for different strains and phenos for a couple grows. People here tend to be invested in making 10/10 grows work not 7/10 or 5/10. Dr. Bugbee is brilliant, and a worthy resource, but to act like people do this for no reason is just your ignorance. Just to make it a little simpler for you, not always necessary means it sometimes is. Many large grows re-use, some smaller growers do with some luck. Most of the commercials that do are getting regular laboratory testing. We don't have the luxury of having already tested many strains and phenos with expensive lab equipment or if something seems off with our staple additions and re-additions then we can do extremely expensive testing. Once again stop asking questions when you already know the answer that you want. Good luck growing.
but where does the lab testing come in?

he basis his mixes off of table 3.... leafs stems roots and fruits...

then he makes premix solution.... table 4...

then the concentration of the solution is a forula but u wouldnt have to do that really just carry the same ec..

but he has already mixed solutions for veg stretch and flower. what would testing do? the mixes are made
 

JonCreighton

Well-Known Member
I mean smaller grow than that. I explained in an earlier post. The more nutes are taken up, the less buffer there is.
does that have to do with the concentration of the solution? or the composition of the solution?

ur at 1.3 ec you drop to 1.2ec and add back the proper nuirtients and get to 1.3 again... is that solution bufferable again or once the buffer is lost its lost

the biggest problem w the paper is ph contorl... im confident i can get the proper nuitrents into the plant at the righ time (probable too confient after hearing form u guys). but how to maintain a ph without effecting the comp and conc of the solution is brutal.. in the paper he talks about a few differnt types of nitrogen for ph control im looking into now
 

Hollatchaboy

Well-Known Member
does that have to do with the concentration of the solution? or the composition of the solution?

ur at 1.3 ec you drop to 1.2ec and add back the proper nuirtients and get to 1.3 again... is that solution bufferable again or once the buffer is lost its lost

the biggest problem w the paper is ph contorl... im confident i can get the proper nuitrents into the plant at the righ time (probable too confient after hearing form u guys). but how to maintain a ph without effecting the comp and conc of the solution is brutal.. in the paper he talks about a few differnt types of nitrogen for ph control im looking into now
My biggest thing for me is I don't like using a lot of ph up or down. When I mix my solution for my res it normally comes out to 5.5-5.6. I don't have to add any ph additives. As the ec drops, so does my ph buffers so I have to add ph additives but it's usually not a lot.
 

Romeo7701

Well-Known Member
I love Q and A's like this ok so I'm gonna play dumb here and ask a question... So let's say we are using 20/20/20 at 1/4 strength which is giving us 250ppm of or base nuits per gallon and we have to add 1 gallon of our pre mixed 250 ppm nuits every day due to consumption, evaporations, ect, ect... When adding this premixed solution would that not refresh and bring our ppm back up to our balance point we are shooting far every time,, hypothetically speaking???
 
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Hollatchaboy

Well-Known Member
I love Q and A's like this ok so I'm gonna play dumb here and ask a question... So let's say we are using 20/20/20 at 1/4 strength which is giving us 250ppm of or base nuits per gallon and we have to add 1 gallon of our pre mixed 250 ppm nuits every day due to consumption, evaporations, ect, ect... When adding this premixed solution would that not refresh and bring our ppm back up to our balance point we are shooting far every time,, hypothetically speaking???
Yes you can bring the ppms back up but if the plants not taking up all the nutes at the same rate, it'll throw the ratio off. Imo that is. I'm not an expert, but it seems logical to me. Lol :bigjoint:
 

Romeo7701

Well-Known Member
Yes you can bring the ppms back up but if the plants not taking up all the nutes at the same rate, it'll throw the ratio off. Imo that is. I'm not an expert, but it seems logical to me. Lol :bigjoint:
Ok because from what I remember in chemistry class PPM'S are a constant as far as if you have 250ppm and put in 250 ppm it doesn't increase until you add more PPM'S so it would stand to reason that as our girls take in what they need out of or mix and we replenish it daily they are happy and we are happy because we don't have to change the reservoir as often... IMO that makes since to me...
 

Hollatchaboy

Well-Known Member
Ok because from what I remember in chemistry class PPM'S are a constant as far as if you have 250ppm and put in 250 ppm it doesn't increase until you add more PPM'S so it would stand to reason that as our girls take in what they need out of or mix and we replenish it daily they are happy and we are happy because we don't have to change the reservoir as often... IMO that makes since to me...
I agree...250ppms are 250 ppms whether in 1 gallon or 100 gallons of water. It's the ratio that makes the difference. I don't believe the plant takes up that exact ratio during feeding. So adding back the exact ratio to a ratio that'll be off, should change the ppms. Ppms don't mean a damn thing if the ratio is off. :bigjoint:
 

Romeo7701

Well-Known Member
I agree...250ppms are 250 ppms whether in 1 gallon or 100 gallons of water. It's the ratio that makes the difference. I don't believe the plant takes up that exact ratio during feeding. So adding back the exact ratio to a ratio that'll be off, should change the ppms. Ppms don't mean a damn thing if the ratio is off. :bigjoint:
So as long as we put in the same ppm and same ratio of NPK the girls love and refresh it when needed with the same ppm and ratio of NPK we should be able to maintain the solution for 1 or 100 grows respectively without having to start over... Theoretically speaking right???
 

Hollatchaboy

Well-Known Member
So as long as we put in the same ppm and same ratio of NPK the girls love and refresh it when needed with the same ppm and ratio of NPK we should be able to maintain the solution for 1 or 100 grows respectively without having to start over... Theoretically speaking right???
it is possible, But you would need to be able to determine what percentage of each nutrient was taken up, and add back only that amount of each nutrient. Obviously, you can be off a bit though. With the right equipment, i believe anything is possible.
 

JonCreighton

Well-Known Member
150 gallons for your first grow? Let us know how it turns out.
first time full hydro... but no the first time making mixes... princiapls should be the same with minor adjustments for what would be in the medium and now has to be in the nuitrient solution... im actually really looking forward to this cycle.. i got 24 new HLG 96v2 wired all over the place and i 6 of those new migro UV 310s that look like the UV light wev kinda been waiting for.. hopefully.. and i think im going to keep far red 730nm lights running durring light cycles this time aswell. i just think research is proving out that you should have some of that in the lights aswell if u can keep the stretching down
 
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JonCreighton

Well-Known Member
So as long as we put in the same ppm and same ratio of NPK the girls love and refresh it when needed with the same ppm and ratio of NPK we should be able to maintain the solution for 1 or 100 grows respectively without having to start over... Theoretically speaking right???
on the right track but not nessisarily...u want to run 20-10-20 the whole time at a constant ec but you have to identify what is being taken out and replace it.. what is being taken out is base don 4 things.. leafs stems root and fruits... table 3 from the paper shows the ratios being taken out (i tried to copy paste but couldnt get it to look readable)

so if u were to think nugs has 3 stages of growth
veg- leafs stems roots
stretch- leafs STEMS roots
flower- roots? flowers

ud want 3 differnt refill solutions to refill the correct ratio to get u back to 20-10-20

iv kind of done this and posted what my ruff estimates of what the refill soltuions would be somewhere above
(i didnt just take bugbees refill solutions from table 4? i think cuz i thought cannabis is a little different than tomaotes but i only made some inor tweaks)... the point i was kinda trying to make w that post was the ratios are all very similar. the veg, stretch, flower refill solutions i mean.. therefore it just doesnt seem that hard especially considering plants can withstand a rather large imbalance w no ill effects.. from what i undertsnd u can run from a 2-1-2 to a 3-1-4 and be safley fine. so u start at a 2-1-2 try to calculate what is being taken out and replace it (w like a 5-1-5 or something) and if u think ur outside 2-1-2 to 3-1-4 dumop it out and start over.. i should stress i keep saying npk but the other stuff matter aswell... especially Calcium

i think the hardest aprt of this is figuring the ph amdjustments into the feralizer numbers. bugbee says in the paper using phosporic acid alone will become toxic for the plants... something about the uptake being so quick if ur constaly phing w P ur going to be at toxic levels in the plant. He reccomends using nitric acid as a form of ph control and says it can "supply half the nitrogen".. iv been working this out and without any nitric acid on me its hard to see X ppms of nitric acid will drop X ph and all that but i think its probable going to work better with the nitric acid...
 
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Romeo7701

Well-Known Member
OK if I may speculate and add something here if your PH is at 6.5 and your feeding
lets say 6 plants in hydro and after a week you check your PH it has dropped to 5.5
and you want to get it back up to 6.5 PH and top off your reservoir, could you not just
add the needed solution back to the reservoir at 6.5 PH to bring it up and just plain Ro
water with your solution if it is high?? just asking never tried bringing it down
 

Hollatchaboy

Well-Known Member
OK if I may speculate and add something here if your PH is at 6.5 and your feeding
lets say 6 plants in hydro and after a week you check your PH it has dropped to 5.5
and you want to get it back up to 6.5 PH and top off your reservoir, could you not just
add the needed solution back to the reservoir at 6.5 PH to bring it up and just plain Ro
water with your solution if it is high?? just asking never tried bringing it down
Depending on how much you use, Plain ro water should bring ph up from 5.5.
 
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