Hypo into TTM?

[Kurkis493]

I have a Milwaukee Refractometer (brand new, arrived a week ago) that I used to put some new fish I am QT'n into hypo.

I picked hypo over TTM because their are some tough to keep anthias and I didn't want to stress them chasing them around the tank because they need to get eating.

I did have to treat this QT system though because a Hippo tang was infected with ich.

Now - This refractometer despite very carefully using the sample water to zero out, and using new water and letting it sit on the lens for 45 seconds is not giving me very accurate results it seems....

Last night while reading I had a salinity of 1.009 and today when I checked I have a reading of 1.012 - This is 8 hours after my last check....

I have 4 QT tanks set-up using all the same water, equipment etc... In one of the QTs I woke-up to 4 dispars (easier to keep) dead. Yesterday these anthias were out swimming and eating.

So something I did over night owned these fish.... I have a Borbonius that since going into Hyposalinity has stopped eating all together but is active.

Using a refractometer (which only goes down to 1.015) and a hydrometer I took the water down to 1.012 (according to the hydrometer, which I know is off). When my Milwaukee arrived, I used it to bring the salinity down to 1.009 over the course of 2 days from what was infact 1.012. So I do not feel I screwed up bringing the fish down into hypo.

I also have been dosing Stability on all 3 tanks (per the bottle) daily and the tank has been getting alot of good WCs because I was lowering salinity.

My question is this - You are supposed to hypo for 4 weeks and then bring the salinity back up. The fish have been in hypo for many days now and the ich symtoms of ich have gone. What if I maintained what I believe to be hypo for 2 more days and Wednesday morning did transfers of all the fish to new systems....

Removing the fish just like I have done TTM - Wouldn't that break the cycle since the parasite should be technically be off the fish at this point and the eggs are not laid on the fish itself?

For peace of mind, I feel more comfortable just transferring fish to a new system at same salinity and then letting it over natural evaporation rise over the course of a couple of weeks....

Can somebody point out the flaw in my logic?

 

[snorvich]

Digital refractometers (and in fact all refractometers, and most measurement instruments) are accurate only with +/- the standard error of the mean. Using them for highly accurate measurement of hyposalinity is likely to result in less than wonderful results. Even if executed correctly, hyposalinity may require a longer execution time than 30 days since it only affects one stage of the life cycle and that stage is at the back end rather than in the highly deterministic front end.

 

[Kurkis493]

Is there nothing that is 100% accurate?

I've had the Pinpoint Salinity monitor, refractometers and now this Milwaukee refractometer and it seems that none of them are 100% even with calibration...

I've ordered multiple bottles of Pinpoint's salinity calibration fluid in the past only to find that all 3 bottles at room temp using the same tool of measurements were all off by .01

I thought in this case purchasing a brand new unit would be perfectly calibrated and something I could count on...

I will just prepare to QT the rest of these fish in a tank transfer method....

The only option left to me feels like I could try a Veegee refractometer but I'm not sure what good that is if the calibration fluids are not even accurate themselves...

I've read that the handmade tropic marin tool for measuring salinity is dead on accurate and the best thing to use as a "base" is their truth to this?

 

[Dmorty217]

I would skip the hypo all together since it will in fact be more stressful than just doing the TTM. Like Steve mentioned nothing is 100% when it comes to refractometers

 

[Deinonych]

I would skip the hypo all together since it will in fact be more stressful than just doing the TTM. Like Steve mentioned nothing is 100% when it comes to refractometers

I agree. TTM isn't stressful. If you are concerned about chasing fish trying to catch and move them, lowering the water level in the tank to a few inches makes them really easy to catch without stressing them. Also, since transfers are usually done in the morning before lights on, the fish are usually pretty sleepy and don't race around.

 

[Kurkis493]

Yeah I agree. I usually always to TTM / Prazi...

I have some wrasses in this QT situation + these anthias and I thought maybe going back to hypo would be better in this case, especially for the wrasses since Prazi is problematic for them.

I will let salinity rise-up and TTM later this week.

I've started to raise-up the salinity a bit now just to make sure I am not in some danger zone for the fish.

 

[snorvich]

Is there nothing that is 100% accurate?

Well, I have a calibrated temperature thermometer that is 100% accurate but it is a very expensive instrument. Other than that, where you pay for 100% accuracy, best you can hope for is a small standard error of the mean.

 

[ThRoewer]

I usually prefer hyposalinity for the same reasons and find it to be quite easy to maintain.

As for the measuring accuracy: There is hardly any measurement instrument that is 100% accurate. In general, if you want higher accuracy you have to spend more $$$.

But your density going from 1.009 to 1.012 over night doesn't sound like a refractometer accuracy issue but may just be a matter of evaporation. Depending on your water movement, tank and room temperature and open tank surface you can evaporate quite a lot in just 8 hours.
When doing hyposalinity you need to mark the water level and refill with RO regularly. I also cover the tank to about 80 to 90% to limit evaporation.

The other option for the higher reading 8 hours later may be that you didn't clean the refractometer or sample transfer equipment well enough. I had some readings that were too high too and after a thorough cleaning of the refractometer and sample collector they came back to where they should have been. By now I stopped using the eyedropper for sample collection and use a glass stick instead because it is easier to clean and automatically transfers just the right amount of water.

If you want to do TTM I would still recommend to lower the salinity. For once it reduces stress for the fish and it also saves you salt/saltwater. The latter is a factor for me because I don't have the space to mix my own saltwater and have to buy it and carry it home in 5 gal canisters.
For TTM I would fill my 10 gal quarantine tanks with one canister of saltwater at 35 ppt and one canister of RO water. This gives you a salinity of 17 to 18 ppt (~1.012).

 

[snorvich]

A Milwaukee Refractometer has a standard error of the mean of +/- 0.002 which means that a reading of 1.009 can range from 1.007 to 1.011. Just an FYI.

 

[Dmorty217]

A Milwaukee Refractometer has a standard error of the mean of +/- 0.002 which means that a reading of 1.009 can range from 1.007 to 1.011. Just an FYI.

Plus if you don't clean the glass that the sample goes on well enough your readings will jump all over the place. It's a nice tool to have but I have the old school refractometer as a back up

 

[snorvich]

Plus if you don't clean the glass that the sample goes on well enough your readings will jump all over the place. It's a nice tool to have but I have the old school refractometer as a back up

And the same issues apply when reading any other measurement value. Low level phosphate measurement being a prime example.

 

[andy01748]

I have a Milwaukee Refractometer (brand new, arrived a week ago) that I used to put some new fish I am QT'n into hypo.

Now - This refractometer despite very carefully using the sample water to zero out, and using new water and letting it sit on the lens for 45 seconds is not giving me very accurate results it seems....

Last night while reading I had a salinity of 1.009 and today when I checked I have a reading of 1.012 - This is 8 hours after my last check....

My experience with the Milwaukee has been pretty good for a hobby grade instrument. Even though it is only rated +/- 0.002 SG, I have found it more precise and accurate than this rating. In terms of accuracy, it has always been right on when checking against calibration fluid or verifying the SG from an LFS purchase, as I always ask what they run their SG at. Of course, I may just be lucky, understanding that manufacturing tolerances may not be that tight for this relatively cheap instrument.

Given that, a couple of things may help you get more accurate and precise readings.

First, make sure the area you use it is the same temperature where you store it. I don't know where its ATC sensor is located, and it is possible the sample well may be at a different temperature than the ATC sensor, leading to inaccurate results. I always take it out from its storage cabinet under my aquarium and let it sit on my counter for 30 minutes to make sure the entire instrument is at a uniform temperature before using.

Second, 45 seconds is a long time to wait to take a reading, and the sample may have started to evaporate. I find that 10 - 15 seconds is adequate for the sample to equilibrate to the temperature of the instrument and give a stable reading. I add just enough sample so that it makes contact with the metal around the sensor, so that the sample isn't thermally insulated from the instrument, and can cool to the instrument's overall temperature.

Third, before and after each reading I clean the sensor using a Kleenex, and confirm that RODI gives a 1.000 reading. Many times I get a number like 1.001 or 1.002, and need to re-rinse with RODI and rewipe to get a 1.000 reading. Whatever you use to clean between samples (Kleenex, cloth, etc.) remember because it is dry doesn't mean it won't leave a salt residue behind, especially if you have used it several times. Any left over residue will give an incorrect high reading on the next sample.

Good luck, and hope these hints help you get more reliable measurements.

 

[Kurkis493]

For cleaning the unit, I use several silk clothes used for cleaning camera lenses to ensure I don't scratch the unit and I make sure the lens is completely free of any smudges before taking the reading.

I will say that typically the fluid (after shaking it) that is used to cross check the unit is accurate. Sometimes it will read 1.026 but if I shake the bottle a little more and cross check again it usually reads 1.025.

I always have cleaned and zero'd out the unit before each test.

As for evap - I went to bed at 4am after doing a water change on all 4 QT tanks and I woke-up at 11:45am and found the fish dead. I definately didn't evap enough water in that time as I have things marked off.

The first reading after seeing the fish dead was a *** - and it came out at 1.012 while at 4am I was sitting at 1.009 -

After making my initial post I went ahead and took 4 cups of sample water from each tank and let it sit a few on the counter come down to room temp which isn't that far off tank temps.

I rechecked everything and got a consistant reading of 1.011 across all tanks.

So in less than 1 hour it dropped .001

I added some cups of water from my display to each of the tanks so if I was in some critical state I got the salinity up a little. All the fish have eaten twice today aside from those that died over night.

Perhaps it was something else but I couldn't imagine what it could be besides dropping the salinity too low....

 

[andy01748]

For cleaning the unit, I use several silk clothes used for cleaning camera lenses to ensure I don't scratch the unit and I make sure the lens is completely free of any smudges before taking the reading.

I assume you thoroughly rinse these clothes in RODI after several uses to get rid of the residual salt?