EI with 20% water change?

JoshP12

Member
Joined
8 Dec 2019
Messages
473
Location
Canada
Will it work?

The root of my question is why does EI style dosing advocate for 50%+ water changes weekly?

I often read to "reset" nutrients ... but why do we need to do that (aside from toxicity - which I suspect has a very high threshold), If excess does matter (I would rather be excess than deficient)?

Also, aside from removing spores, detritus, cleaning water, good husbandry - overall health of the aquarium - does the EI dose have to come with the water changes?

Or can you dose EI with enough of a water change that the nutrients do not become toxic?

Josh
 

Geoffrey Rea

Global Moderator
Staff member
Joined
27 May 2017
Messages
973
Location
Cambridgeshire
The root of my question is why does EI style dosing advocate for 50%+ water changes weekly?

The 50% is arbitrary. It relates to nothing. But the spirit of EI is to dose beyond need. Why do a water change every seven days for example...? Why not six or eight?

The flip side is you’ll probably be unaware of any nutrient imbalances until it’s too late and a week is seven days so a large water change weekly brings things back to a reasonably estimated and acceptable balance that you can work with if you choose the EI root. The seventh day of rest from dosing before a water change also establishes a safety net in helping lean out the water column (people rarely dose what they say they do due to miscalculation, mistakes, lack of excitement in their lives etc).

What your tank uptakes will change across time according to the volume of plant mass as it grows. On a brand new ‘average’ high tech setup (high light, 30ppm> Co2, no plant matter with the advantage of aerial Co2 access) without stock I would personally be happy changing 90% of water for the first month or two. It’s not just inorganic compounds, it’s organic compounds and algae spores you’re removing with a large water change. An established setup after a year... then 50% as a throwaway figure would be fine except if it’s heavily stocked with fish and if you wanted a safety net - in that case it becomes about removing fish waste and water as much as possible to lessen the strain on the system just because you can.

does the EI dose have to come with the water changes?

Without the water changes it ceases to be an estimated index. The water change was the fall back to make the estimating reliable.


Or can you dose EI with enough of a water change that the nutrients do not become toxic?

Yes. You could test or visually observe to check if those volumes are inappropriate to the tanks needs. However, then it’s no longer an estimative index, it’s precision dosing.

Think the point in EI was to find a relatively simple and foolproof way of allowing aquarists to dose their tanks. Is EI the only way, of course not.
 

JoshP12

Member
Joined
8 Dec 2019
Messages
473
Location
Canada
@Geoffrey Rea

Do the ratios matter? In other words, if we just keep dumping fertilizers into a tank and don’t reset the levels, then we are unsure if such an excess will cause an issue or if it will throw something out of proportion?

The water change brings us back within the maximum range of EI, so we know it will be “ok”? And this is what you mean when you say it was the fall back to make the estimate reliable?



Josh
 

Geoffrey Rea

Global Moderator
Staff member
Joined
27 May 2017
Messages
973
Location
Cambridgeshire
Do the ratios matter? In other words, if we just keep dumping fertilizers into a tank and don’t reset the levels, then we are unsure if such an excess will cause an issue or if it will throw something out of proportion?

I don’t know why, but whenever I get roped into talking about fertilisation it feels like I’ve walked into a warzone without a weapon.

My return question is how would you know if you’re on target if you’re aiming for accuracy in-tank? I certainly haven’t got access to a mass spectrometer, I’m not doing hourly tests. Are you using a rich aquarium soil and root tabs, giving the plants an alternative source of nutrients that isn’t from the water column? Is this messing up the generalisations we make about water column dosing?

Also what you’re growing can determine what particular nutrients are in high demand. For example, Pinnatifida heavy scapes seem to be insatiably potassium hungry in my experience. The precious 3:2:1 / Ca:K:Mg ratio you meticulously calculated at water change may only hold true for a day... Can you really generalise that the ratio is present all week between water changes? Does this matter?

Personally I can’t say one way or the other whether ratios matter. It depends if you subscribe to Liebig's law of the minimum wholeheartedly or not.

The water change brings us back within the maximum range of EI, so we know it will be “ok”? And this is what you mean when you say it was the fall back to make the estimate reliable?


In the corner fighting for estimation of ratios.... if you do 80- 90% water changes weekly and have access to your water suppliers water report to give you some idea what your tap water is like, there’s only the 10-20% remaining water in-tank taking you away from the desired spec. In high tech I’ve found this approach very dependable and sufficient mainly because it requires little effort - therefore it gets done regularly and isn’t prone to too many errors.

The second part of your question:

if we just keep dumping fertilizers into a tank and don’t reset the levels, then we are unsure if such an excess will cause an issue

It will kill your livestock before it hurts your plants and is unethical to try if you want animals in there too. Plants produce waste and driving them hard must surpass the limit of the system to sustain itself at some point. The best advisor is personal experience. Why not try running some plant only setups and try some things?
 
Last edited:

JoshP12

Member
Joined
8 Dec 2019
Messages
473
Location
Canada
I don’t know why, but whenever I get roped into talking about fertilisation it feels like I’ve walked into a warzone without a weapon.

Trust me, I am appreciative of perspective and knowledge :).

My return question is how would you know if you’re on target if you’re aiming for accuracy in-tank? I certainly haven’t got access to a mass spectrometer, I’m not doing hourly tests. Are you using a rich aquarium soil and root tabs, giving the plants an alternative source of nutrients that isn’t from the water column? Is this messing up the generalisations we make about water column dosing?

Also what you’re growing can determine what particular nutrients are in high demand. For example, Pinnatifida heavy scapes seem to be insatiably potassium hungry in my experience. The precious 3:2:1 / Ca:K:Mg ratio you meticulously calculated at water change may only hold true for a day... Can you really generalise that the ratio is present all week between water changes? Does this matter?

I suppose that this is what I asked myself earlier yesterday after some reading - and it brings my understanding of fertilization closer. If the intention is to feed plants, then why not give them a buffet, just below < around 6 minutes of this video> 🤣🤣. The location of the access is moot.

The true art of growing plants etc seems to be increasingly complex and I think a way for everyone to access it without needing to know the intricacies is quite nice. It is like when we developed theorems for shortest paths in graphs and then applied it to GPS ... everyone uses a GPS without worrying about how it calculates the shortest path; the unfortunate part is that I have a desire to understand the proof :banghead:. And these open systems are complex and variable ridden.


Personally I can’t say one way or the other whether ratios matter. It depends if you subscribe to Liebig's law of the minimum wholeheartedly or not.

If you do subscribe, then ratios do not matter?
If you don't subscribe, then ratios do matter?


In the corner fighting for estimation of ratios.... if you do 80- 90% water changes weekly and have access to your water suppliers water report to give you some idea what your tap water is like, there’s only the 10-20% remaining water in-tank taking you away from the desired spec. In high tech I’ve found this approach very dependable and sufficient mainly because it requires little effort - therefore it gets done regularly and isn’t prone to too many errors.

Thanks for sharing this experience -- I'm finding EI with large water changes is working well as well. This is probably because of how "easy" the dosing/maintenance has become. I focus more on watching plants, fiddling with light, and fine-tuning CO2 ... well more like playing with it and the hundreds of variables and seeing what happens.

It will kill your livestock before it hurts your plants and is unethical to try if you want animals in there too. Plants produce waste and driving them hard must surpass the limit of the system to sustain itself at some point. The best advisor is personal experience. Why not try running some plant only setups and try some things?

Liebig's law of the minimum ... wife ... 🤣🤣🤣🤣 ... in due time :).

Josh
 

Similar threads

Top