Ok, this may get kind of long.

First, I assume that I am not the only one that has thought of this, so My 2nd assumption is that there are 1 or more fatal errors that make this impractical...

I use EI adapted to my own needs--not by the book. I currently do WCs every couple of weeks or so---and life is good. So, the Strict EI protocol is not being used here--including the weekly reset per 50% Weekly WCs.

I am wondering if the need for WCs can be determined by the build up of TDS's through TDS Monitoring?

Using RO water, then reconstituting it to desired levels, adding ferts and whatever else---Can a "Beginning" TDS reading be taken and the TDS's monitored to determine the build up and WC need?

I realize that there would be some fluctuation so a "Range" would be needed, but what are the fatal errors to this thought process?

I think we explored this idea quite well and the more I thought about it, the worst the idea became.

When plants are involved, they remove such waste from fish that contribute to TDS, you basically are adding Fish food and watching the TDS go up and up.

Many DOC's and POC's do not register on TDS, (it's an electrical conductivity measurement). It does not tell which compounds are accumulating.
Plants expel compounds into the water also. They can change the pH of the water as well as TDS directly and indirectly, we add KNO3 which will certainly increase the TDS, but as plants remove it, can be reduced.

You are welcomed to try it, but it's too general for most applications here with plants, ferts, fish waste etc.

There's arguements that we never need to do water changes also, see non CO2 methods(this also means no Excel).

Regards,
Tom Barr

Ok, Thanx, Tom. That basically explains the inherent problems with the initial thought process.....


I was factoring things like that into my overall scheme, but this is what creates the problems:


My goal was to hopefully limit WCs to about 1/month and roughly and loosely use to TDS ppm thoughts on water quality that the Discus folks have determined....

I am going to Ro for 2 setups and that is really going to make WCs on those inconvenient, time consuming and just a lot of effort.


Thanx Again!

Well, approach the issue from a different view, install a simpler water change method, eg automate(a simple toilet float valve + solenoid) or go with a hard plumbed set up with two valves, one for refill, one for draining.

Larger hoses and faster refills make things easier also. A little plumbing will go a long long way to simplying things and work.

I'm not sure why folks want to avoid water changes with such zeal and yet are blind(it's not just myself/you....... but folks in general) to doing some simple plumbing work to avoid it pretty much from then on.

I tried to avoid water changes, I got more algae, lack luster growth, dirtier tanks relative to tanks that had lots of water changes.

I think if you look at what reasons foklks need to do water changes, it gets down to growth rate.

When we add lots of light, it'll require more. When we add CO2, it'll require more.

If we go non CO2, non high light, we have a system that's a lot easier to balance without any water changes.

If you seek fewer water changes, consider that method. Yes, there are trade offs, but they are not bad.

If you want to do once a month water changes, then perhaps some test kits and good testing procedures are in order to keep things consistent. Doing EI and only doing a water change once a month is getting out there a bit too far for most folks, those with more experience and understanding of the trade offs and sign of a time to do a water change or else things are going to get bad can do this without test kits.

That's the trade off there.
Some folks only want to change 10% at a time, there's an obvious trade off there.

Basically......you do not get something for nothing. There is no trick, only trade offs.

Even if I can get away without doing a water change for 2 months, the tank will always look much better if I did them every week. Amano, Mr Knott and others will agree with that.

I think given your own goals, automated water changes, or semi automated with hard plumb so all you do is turn a valve to drain, turn a valve to refill are good options and would solve most of the issue and allow you the most flexibility should things go wrong ever.

Be better for the fish also.

If you run say low light, say 1.5 w T5's etc and good CO2, then getting away with onmce a month say 40-50% will work, you'll likely need to test for some time before you get ahandle on things and I'd suggest making the calibration solutions for NO3 and getting a Lamotte type of test kit.
Two weeks is easier to get away with without having to resort to test kits.

So there are a number of solutions for the water change issue.
You can pick from there.

Regards,
Tom Barr

Hi Tom,

I do run low to medium light tanks, so I dose a couple of times/wk. I run C02 in all, but 1--it gets Excel.

I have a semi-auto-WC system setup on three tanks. But switching to the RO for 2 other setups has brought along new problems that I just need to sort out. RO is Brand new to Me, so I've been, and still am, in the Learning Curve. It will just take some time. I may go to a Continuous WC System, but it would just be a "Continuous" setup run intermittently--I don't need to change 75-100g/day, so I would need to put the RO on a solenoid valve and timer. Then I have the problem of maintaining Gh, Kh, and the Blackwater that I add. So, these are just problems I need to sort out.

Personally, I think 2 of the reasons that I have been stretching out my WCs are: 1) I guess I just need to "go there" to see for myself, and 2) I've been distracted by many other things Aquarium related, so I just keep putting it off--at least somewhat Willingly.

I originally assumed that the TDS WC was not practical, but I really couldn't sort out why. So, I had to ask!

BTW, the whole TDS WC and 1/month thing wasn't that important. I was hoping I could use the TDS's simply to "Notify" me of when a WC was needed---whether its 1/wk, 1/month, 1/yr! I was hoping more for a "Monitoring" system than a postponement system. Hope that makes sense.....

Many Thanx!