100% Water Change????

[Katy]

I see many references to this, but how does one do this without stressing the fish?

Even if water parameters match, if I do 2 50% WCs back-to-back, that is still only 75% water change.

I want to make 100% sure all the Rid Ich I have been using is out of the tank before I start internal parasite treatment. Have the UV on (supposed to deactivate malachite green), have trouble opening filter due to broken top to add the charcoal

Thank you so much, and I am sorry for all the many questions, but these fish have so much personality, and I really really really want to do right by them!

[Marcos Mataratzis]

Hi Katy,

Even if you do 100% WC you will not get rid of ich cause only one out of three stages of the protozoa will be free on the water. Other two will be in the fish and on the gravel, rocks, leaves and even the glass of the tank.

Read this:

Dealing with ich

Good luck!

[Katy]

No, I mean to get rid of the medicine for the ich -- they have finished the treatment (I sure hope !!!)

[Marcos Mataratzis]

You can use Active Carbon or Purigen to adsorb medicine.

[Diana]

There are several ways to do such large water changes. Some are more stressful than others. Basic to all methods is to prepare water that is as similar as possible to the water in the tank. Measure GH, KH, pH, TDS... and make them the same. Match the temperature, too.

Method 1:
(Very stressful, but very thorough) remove fish from tank. Turn off equipment.
Use the water removal to also do a REALLY thorough gravel vac, move all decor...
Also, clean the filter media, hoses and everything. You might not want to use water removed from the tank, so use some of your prepared water.
Then put the substrate and decor back the way you want it.
Refill the tank with the new water. Pour this water in over a plate or plastic bag so it does not stir up the substrate.
Start the equipment.
Add the fish, but do not add the water from their bucket. Along with the Rid Ich and possible Ich organisms, the fish also produce excess ammonia and stress hormones and you do not want any of this going into the new tank. You can also use this opportunity to dip-treat the fish, if you want (more stress)

Method 2.
Less stress, but also less thorough.
Do several smaller water changes. Add them up to about 200% water change, to have a better chance of getting out more of the Rid Ich.
For example, if you are doing 50% water changes, then do 4 of them (4 x 50% = 200%)
If you are doing 25% water changes then do 8 of them...
These water changes ought to be back-to-back, or several one day, and several more the next day. Include as much gravel vacuuming as you can. You could vacuum perhaps half or a third of the gravel with each water change.

Method 3:
Least stress, but most questionable removal:
Set up the new water and start pumping it in as you are removing the old water. I generally allow the water in the tank to drop a few inches so that any inequality in the rates will not overflow the tank. Again, gravel vacuum as much as you can.
If you set up 2 of these, equal to 200% water change, I think you will be getting rid of a very large % of the Rid Ich. Certainly also clean the filter during this procedure, or any other.

Other idea:
Hang a bag of activated carbon in the flow of water coming out of the filter, entering the tank. The water will pass through the carbon, so a lot of the Rid Ich will get removed this way. As part of any of these water change ideas, also clean the filter. If the filter is difficult to access, still make the effort.

[Katy]

Thank you so much for the information! All of your answers are so helpful and detailed!

[Keith Wolcott]

I could not resist doing the math to see how Diana's method 2 and method 3 compare.

Method 2.
Four 50% water changes reduces the Rid Ich down to 6.25% of the starting amount.

Eight 25% water changes reduces the Rid Ich down to 10.01% of the starting amount.

For Method 3, if we assume that the water is mixing very well as you do the exchange and you change 200% then it reduces the Rid Ich down to 13.53% of the starting amount.

Thus, I would say these methods work pretty well.

[Katy]

Gotta love a geek

Now, what formula did you use for #3?

I have already done 2 50% changes, have water out-gassing for the next two

[Keith Wolcott]

Katy- There's not really a formula for method three, but it is a standard second semester calculus problem where you set up a separable differential equation and solve it.

[palaeodave]

I think anyone who comes on this forum is one kind of geek or another

Professor Wolcott just happens to be a particularly useful kind when one has a mathematical problem! (You saved me on my undergrad dissertation. Btw, I got 1st class honours for that, in no small part due to you pointing me in the right direction with that multivariate analysis stuff so thank you very much!)

[Katy]

Yeah, I had figured out he was a math professor. And I am enough of a geek to want to know the formula so I can see if I can parse it (loved calc many years ago)



Meanwhile, I am getting my hands on some open-but-unused IV tubing for dripping water into the tank at a controlled rate. Should be great for acclimatizing when we get more fish, too

[Keith Wolcott]

Thanks for the complement Dave and I am glad that your dissertation turned out so well.

[Diana]

The few times I drip acclimated I simply tied a knot in some air tubing and snugged it tight enough to create about one to two drips per second. I keep my house too cold to do that, though, unless it is summer.