# Using a TDS meter in conjuction with EI dosing



## plantbrain (Jan 23, 2004)

Frank suggested using a TDS meter to know when things get too high (whatever too high? is) regarding usage of EI.

If the TDS climbed say 100ppm then it would be time for a Water change. You could set whatever increase in TDS levels you want based off the the tap water starting point.

This would extend out the water change frequency further than say the commonly used weekly schedule etc. So until you got further out, you simply would not need to do a water change unless something appeared wrong.

TDS meters are cheap(30$ ebay) and easy to use and one meter could quick test a dozen tanks.

This would not tell you _which nutrients_ are climbing, but it would tell you when you'd need to consider a water change without having to do any testing, just a quick meter read.

This could extend out the water changing frequency to 1-2 months I'd expect and allow a little more conservative dosing/correlating with TDS and adding excess nutrients in a very simple way that requires one simple parameter as a gauge.

I'm not sure how much of an increase in TDS is required, but an arbitary point can be picked (say an increase of 50ppm before a water change is done and go from there) and see how long it can be maintained without any negative plant growth issues before a water change. Dosing less could be done to extend out the WC frequency also, but it will not tell you which nutrient is doing what.

This relies on one cheap reusable instrument than can quickly and easily measure many tanks rapidly and is very simple in terms of use & maintenance.
You cannot test every single individual parameter anyway.

Thanks Frank

Regards, 
Tom Barr

www.BarrReport.com


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## plantbrain (Jan 23, 2004)

A follow up on which nutients cause an increase in TDS ppm: simply measure before and after dosing.

This will give you an idea of what each adds, it does not tell you how much or what is there as the TDS increases ........

But you can estimate what you think the weeds are using and not using also and play around the balance that out with a little testing.

Regards, 
Tom Barr


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## plantbrain (Jan 23, 2004)

And a bit more backgound for use with hydroponics:

http://www.tdsmeter.com/abouttds_hydroponics.html

There is no reason why this cannot be applied to aquariums with good results.

Regards, 
Tom Barr


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## chiahead (Dec 18, 2004)

here is a decent link on TDS meters and what TDS is

http://www.tdsmeter.com/
or this one
http://bcn.boulder.co.us/basin/data/NUTRIENTS/info/TDS.html

I would like to know what is a limit range as well, even though I still ike to test and make sure I am at the right levels from time to time.


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## plantbrain (Jan 23, 2004)

Well, it might not work and it certainly has limitations, but so does every testing method or routine.

Hydroponics folks seem successful using it and it does simplify things a great deal.

Main thing is getting around the human part, most hate testing, water changes and other excuses to avoid work

You can go longer and tweak things a number of ways using EI, (at least 3 besides this TDS method using EI), but this might be fairly simple for folks also.

The point is to use the TDS to say when a water change is needed.
EI can be used in that manner and water changes applied using the TDS meter.

I have only recently found max levels for NO3, around 100+ ppm if you use KNO3.

So we have a pretty wide range before things get sour in terms of fish health.
PO4? No clue still. More than 5ppm.

Folks certainly can estimate for 2-3 weeks, then a TDS meter may help and extend the WC frequency out even further. And it's simple to use.

It's not that hard or difficult to estimate a tank's max uptake and dose accordingly. The TDS meter could be used to dose more conservatively to avoid as much build up and thus fewer water changes.

Edward also suggest using these for total build up for PPS for a water change. Nothing new here except applying it for WC as Frank suggested for EI dosing.

I suggest dry dosing of most ferts, he suggest his solution based ferts, EI can easily be used with solutions and his solution recommendations as well and add milliliters instead 1/4 teaspoons etc for greater accuracy and control if you so chose....but it's not needed to grow plant well. PPS suggest this, and adds pretty much the same deal, PO4, NO3, Traces and a GH, basically I suggest with EI 3 main things and GH if you do not do water change like on non CO2 plant tanks, or the GH is low or you go long peroids without water changes.

The end result is the same in terms of plant nutrient supply.

PMDD did the nutrients added to solution over a deacde ago for planted tanks. There was also some discussion on the APD, heck, I forget when about TDS usage for water changes.

Here's some old discussion about it from Wrigth from the bay area:
http://fins.actwin.com/killietalk/month.200009/msg00361.html
http://fins.actwin.com/killietalk/month.200405/msg00544.html

For killis and other fish, he uses a 2x factor before change is needed.

http://fins.actwin.com/aquatic-plants/month.200006/msg00123.html
http://fins.actwin.com/killietalk/month.200201/msg00382.html

That's fairly simple.

Regards, 
Tom Barr

www.BarrReport.com

Regards, 
Tom Barr


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## BluesBoy (Jul 2, 2004)

Sorry, before I found this thread I started a new one on this subject  
http://www.aquaticplantcentral.com/forumapc/showthread.php?t=10953
Comments and ideas are welcome.


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