Can someone explain to me how to top up a reservoir (rez)? I just don't get it...

Good info, really old thread though

johnwest221 said:

Minerals will build up in the reservoir and your plants may not use all the nutrients equally, so you’ll definitely want to change the entire reservoir of water at least once every 7 days

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This depends on the size of your reservoir of course (related to the amount of plants or surface)
When you have a really large reservoir for just a small amount of plants or small surface, it will take much longer before ther will be an imbalance of elements in your nutrients solution.
So then theoretically you can change your res just before the nutes start to smell funny.

johnwest221 said:

The plants like the 10-15min of oxygen they get while you’re changing the water, but don’t let any of the roots dry out.

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It will take a while before roots really dry out. Then can survive without water for several hours. Not that it is a good idea perhaps, but no need to hurry (and make mistakes) while changing the water.

• The easier way to do this is to make an extra batch of nutrient water and use that to top off your reservoir. Nutrient water can last for at least 2 weeks after being mixed.

• Minerals will build up in the reservoir and your plants may not use all the nutrients equally, so you’ll definitely want to change the entire reservoir of water at least once every 7 days.

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This is basically what I do, I make double the amount of water my res needs in a separate tote, I ph it, nute it, etc. only thing I don't add is any humic/fulvic acids and bennies. I drain my res and clean it and then refill it from this extra tote and just add the acids/bennies during the refill. Then during the week when I need to top off, I know my water is already good and don't have to worry about it, just fill it up from the extra tote and add acids/bennies as needed per amount added. After a week or so I drain them both and redo it all again. Usually I do the extra tote a day ahead of the res drain/refill.

Top up with 33% solution adjust as needed and do a res change once you have added back the volume of your system to prevent nutrient imbalances.

If your ppm is is dropping after this bump up the solution and plants likely would benefit from an overall increase in ppm of the system.

If your ppm is increasing after this you likely feeding to high of ppm.

It will never be perfect but shoot to get close and adjust adback to steer ppm, should not have issues

Aqua Man said:

Top up with 33% solution adjust as needed and do a res change once you have added back the volume of your system to prevent nutrient imbalances.

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Could you explain this more in detail please.
I also struggle with what is the best method.
For example: why not top up with the same solution as the original solution in the res?

This is a good topic,Ive found my plants and my pH are much happier when my top offs are 1/3 rd of my res ppm.

johnwest221 said:

Minerals will build up in the reservoir and your plants may not use all the nutrients equally, so you’ll definitely want to change the entire reservoir of water at least once every 7 days.

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I've been hearing "change the reservoir every 7 days" for 20 years now. It was the one part of my hydro system that I hated -- I didn't want to dump good nutes down the drain...ever.

This current run I rebuilt my entire system and part of that was the Torus Hydro for pH management. One side-effect of this is that it does ion-exchange to keep the pH in check instead of adding an acid or base to the mix. For the first time ever I ran an entire veg run from seed w/o a single reservoir change. There were no signs of lockout, the reservoir didn't smell and the solution was still crystal clear like the day I mixed it.

I do top-offs every 2-3 days. I refill my reservoir with RO to my "full line" and then use the flow meter to see how much water was added. From there I do the math and add the nutrients at full strength for however much water I added. (I have concentrated Jacks 321 A and B premixed and always ready to go.)

SuperiorBuds said:

I do top-offs every 2-3 days. I refill my reservoir with RO to my "full line" and then use the flow meter to see how much water was added. From there I do the math and add the nutrients at full strength for however much water I added. (I have concentrated Jacks 321 A and B premixed and always ready to go.)

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So no 33%.
Let's say you add 20 gallon. You use the same amount of nutrients that you normally would use if you would have a reservoir of 20 gallons?

Keesje said:

So no 33%.
Let's say you add 20 gallon. You use the amount of nutrients that you normally would use if you would have a reservoir of 20 gallons?

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yeah you would just dose the amount of water you added with the amount of nutes you need. So like this

Start of week, 20gal res
dosing nutes at 3ml/gal = 60ml of nutes
lets say ppm is 600 and is either staying the same or slowly dropping over the week

after a week your res is half full, still hovering around 600ppms, you need to add 10 gallons to get it back to full 20gal res.
You add 10 gallons of water
Well now your ppm's are half(300ppms) of what they were before you topped off so you have to add some nutes to get it to roughly the same level as it was before. You know you added 10 gallons of water and you know you were dosing at the start of the week at 3ml/gal and the ppm's were holding steady or slowly dropping which is what you want.
You would add 30ml of nutes(3ml/gal x 10 gallons) to get your ppm's back up to the same level they were at the start of the week.

Sometimes you need to add a little less nutes if ppm's have been rising all week, sometimes you need to add a bit more if ppm's were falling quickly every day but that's basically it.

Keesje said:

So no 33%.
Let's say you add 20 gallon. You use the same amount of nutrients that you normally would use if you would have a reservoir of 20 gallons?

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Correct.

I could also do it like this, if I wanted... If my reservoir needs 20 gallons I could mix up a batch of 20 gallons of RO w/ full strength nutrients and add that into the reservoir. (I did this for many years.) The problem I found with that is I'd mix up 20 gallons, and end up only needing 18.

So I guess theirs a diff if you ad top up once a week or every 2 days. Different size systems I guess. I’m kinda anal about keeping level the same.probably makes no difference though.

SuperiorBuds said:

This current run I rebuilt my entire system and part of that was the Torus Hydro for pH management. One side-effect of this is that it does ion-exchange to keep the pH in check instead of adding an acid or base to the mix. For the first time ever I ran an entire veg run from seed w/o a single reservoir change. There were no signs of lockout, the reservoir didn't smell and the solution was still crystal clear like the day I mixed it.

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What you call a 'side-effect' of the Torus Hydro (keeping the pH in check) is the main purpose of such a device, as I understand from their website.
In what way do you think it helps the EC of the nutrient as well?

Keesje said:

Could you explain this more in detail please.
I also struggle with what is the best method.
For example: why not top up with the same solution as the original solution in the res?

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Ok so this is a guideline that should be close if the starting ppm is in the prime zone.

For me I like to see a slight increase in ppm as the plants drink not much but just a bit. But if I too up with just water the ppm goes way down pretty quickly.

33% is a good starting point but will need adjusted and will never be perfect you will always have to adjust if you are shooting for perfect numbers but if you system ppm is in the sweet spot for stage of growth then it should be close enough to get you to the next res change without much of a ppm change at all.

I do a 25-50% change at a time but that's for different reasons and I won't go into as it complicates things from what your asking.

So if you add back a 33% solution and the ppm is the same that's about where ya wanna be in a perfect world IME. Now this changes later in flower but I'm talking about veg and most of flower excluding the last 3 weeks.

If after adding back the ppm is lower you can raise the overall ppm of the system. I don't like to do more than 10-20% increase in ppm at a time but you will find you are slowly almost constantly increasing the ppm until after stretch. This is because of the growth rates and changing needs of the plants. So if you find you need to up the ppm I do so through my add backs so sometimes I may add back say 66% or more to adjust the res ppm then add back 33% next day and see where I'm at. It's all a guideline no hard fast rule. But it allows you to see and adjust the overall plant needs for concentration daily. Rather than do a res change and increase the ppm once a week it's more gradual and constant keeping the ideal ppm very close to ideal if that makes sense. By doing daily tops up with ppm check after adding back 33% you can see if you need a higher overall ppm which is usually the case once things get past week 2 you see almost daily need for a slight increase and this is why 33% is not a rule but a guide or a target per se.

If you add back 33% and the ppm is almost the same you know you are very close to being right on target for the plants. Of course it Varys with strains etc but it's a good place to start and then fine tune based on the ppm changes and plant responses.

Once you add back the volume of your system then do a complete res change out. For me it's almost 3weeks to a month before my first one and gets to as much as 5days by end of stretch. That prevents nutrient imbalances and prevents wasting a shit ton of nutes on unnecessary water changes

Not sure if that answers your question but if not just ask again.

I am still confused. Hahaha. I am confused about what you mean with '33%".

I will give it another try.
Let's say you have a res of 60 gallons with an EC of 1.2
After a few days 20 gallons are gone and there is still 40 gallons in the res.

Now there are 2 options:
1. You make a new batch of 20 gallons with an EC of 1.2 and with that you refill your res. (33% of the the res is now new water)
The EC in the refilled res will be around 1.2 (40 gallons with 1.2 and 20 gallons with 1.2 = average of 1.2)

2. You make a new batch of 20 gallons with an EC of 0.4. (33% of the amount of nutrients)
The EC in the refilled res will be around (40 gallons with 1.2 and 20 gallons with 0.4 = average of 0.93)

Holy balls this is an old thread.

to top off water:
Add fresh water to evap nute mix in res to same level as initial solution level....
Done

Keesje said:

I am still confused. Hahaha. I am confused about what you mean with '33%".

I will give it another try.
Let's say you have a res of 60 gallons with an EC of 1.2
After a few days 20 gallons are gone and there is still 40 gallons in the res.

Now there are 2 options:
1. You make a new batch of 20 gallons with an EC of 1.2 and with that you refill your res. (33% of the the res is now new water)
The EC in the refilled res will be around 1.2 (40 gallons with 1.2 and 20 gallons with 1.2 = average of 1.2)

2. You make a new batch of 20 gallons with an EC of 0.4. (33% of the amount of nutrients)
The EC in the refilled res will be around (40 gallons with 1.2 and 20 gallons with 0.4 = average of 0.93)

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IMO it should always be option 1. You want to keep the ppm levels the same throughout the grow for the levels you need. If the plant is keeping ppm's stable throughout the week then when you top off you need to keep roughly that same ppm level, if the ppm's are dropping before top off then you need the ppm's a little bit higher when you top off. If the ppm's are rising then you need to lower the ppm level when you top off.

HolyAngel said:

IMO it should always be option 1. You want to keep the ppm levels the same throughout the grow for the levels you need. If the plant is keeping ppm's stable throughout the week then when you top off you need to keep roughly that same ppm level, if the ppm's are dropping before top off then you need the ppm's a little bit higher when you top off. If the ppm's are rising then you need to lower the ppm level when you top off.

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Yes but you also need to adjust for the increased needs of the plant as it grows. That's what I'm talking about including here. Sure you can just go by a guideline but why not go one step further and make sure your plants are getting the right ppm. This is done by monitoring the amount they eat and doing top ups and ppm readings daily or every other day.

Aqua Man said:

Yes but you also need to adjust for the increased needs of the plant as it grows. That's what I'm talking about including here. Sure you can just go by a guideline but why not go one step further and make sure your plants are getting the right ppm. This is done by monitoring the amount they eat and doing top ups and ppm readings daily or every other day.

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yep I agree, I personally take ph and ppm readings morning and night and adjust daily as needed.

Keesje said:

I am still confused. Hahaha. I am confused about what you mean with '33%" and likely more than 100% in order to raise the overall ppm of the system.

I will give it another try.
Let's say you have a res of 60 gallons with an EC of 1.2
After a few days 20 gallons are gone and there is still 40 gallons in the res.

Now there are 2 options:
1. You make a new batch of 20 gallons with an EC of 1.2 and with that you refill your res. (33% of the the res is now new water)
The EC in the refilled res will be around 1.2 (40 gallons with 1.2 and 20 gallons with 1.2 = average of 1.2)

2. You make a new batch of 20 gallons with an EC of 0.4. (33% of the amount of nutrients)
The EC in the refilled res will be around (40 gallons with 1.2 and 20 gallons with 0.4 = average of 0.93)

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Ok so you have a 40 gal res and say daily you plants are drinking 10gal. Your EC is 1.2.

You mix up 10 gal with 33% concentration. 0.4 add it back to the res. Your EC is 1.2 after add back.. your perfect.

Your EC is 1.3 your res solution of nutrients at 1.2 EC is to high for the plants and the next add back will be used to lower the over all EC of the res.

Your EC is 1.0 your res solution of nutrients at 1.2 is to low and your next add back will be higher than 33% to increase the overall concentration of the system.

If they are drinking 10gal a day and you have a 40gal system. After 4 add back you will dump and make a fresh res.

Now like I say this is a guideline. Not a hard rule. You will see that different strains actually require different overall concentrations as they may be heavy or light feeders. This just gives a method of evaluation for you overall nutrient concentration and shows the plants feeding habits. Rather than some arbitrary number you are using the info your plant is giving you to adjust the feed according to its needs if that makes sense

HolyAngel said:

yep I agree, I personally take ph and ppm readings morning and night and adjust daily as needed.

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I'm keeping it simple here but I also do the same. Readings before and after add backs.