YWG - Day 6 and still kicking

[Rascal]

I have to disagree with the high alkalinity assumption.

Rhetorical question: Why is pH low but alkalinity is high?

 

[parshmar]

Good luck and I hope that fixes the problem.

 

[NicoleC]

I have to disagree with the high alkalinity assumption.

It's the only water parameter off. Otherwise they were developing well and were energetic up until a couple of days ago.

Rhetorical question: Why is pH low but alkalinity is high?

Because, as I said, I was overusing buffer, which was raising the Alk. Buffer doesn't solve underlying pH preblems, which are common in larval tanks.

 

[Rascal]

Do you have any of that 'old' water left, or any in vessels with a similarly low pH?

 

[NicoleC]

No, I dumped it. But I did the oxygen test first -- it had very little effect on the pH.

If I could ever get my live phyto rolling, I might be able to solve much of the low pH issue by using live phyto to tint the water green.

 

[rsman]

how exactly did you do your oxygen test, if it was a kit which one, if it was ph test with an airstone where were you, how long did you let the air run, how high was your alk and which buffer did you use ??

 

[NicoleC]

I did the airstone test outside; I went from 7.9 to 8.1 in 30 minutes.
Alk... well, it went off the chart. The Salifert test mexes out at 16 dkH.
Buffer is SeaChem Reef Buffer. Perhaps straight sodium bicarbonate baked into sodium carbonate would have been a better choice.

 

[Rascal]

IMO, a jump in pH from 7.9 to 8.1 is substantial.

I did the oxygen test first -- it had very little effect on the pH.

If you aerated the water for 30 minutes and it rose 0.2 units, that is evidence of residual CO2. CO2 + H2O produces carbonic acid. Buffer may or may not raise the pH, but it would definitely raise the alkalinity.

My advice would be to continue aeration. In the end, what's there to lose?

 

[NicoleC]

Aeration has been nonstop since before they hatched, per SOP.

 

[rsman]

with an alk level above 16 the small jump in pH from 7.9 to 8.1 means a HUGE jump in O2 remember that alk should have stoped any change from happening, you had a good size change there. you have O2 problems, at least see if you can screen off an area and add an airline to that. or otherwise stir the water frequently.. or bring in outside air. also anything that will raise the amount of airation going on.

 

[NicoleC]

Inside air is very good on O2. For one thing, the window is open. Also, my reef tank is at 8.4 and steady, and if CO2 levels rise I see that tank drop right away.

Interesting idea about screening off an area so you can aerate more vigorously. I don't have any mesh small enough (say 250 or so) to keep the gobies out. I may have some loose weave 100% polyester fabric but I'm not sure what I'd have to do to really get the sizing out. I doubt fabric sizing is good for larvae!

I'll have to dig around here and see what I can find.

 

[rsman]

remind my empty brain .....

what are you rearing them in again ??? and how high is the water level ??

 

[NicoleC]

Half full 10g.

I found some fine toile. The openings are a little too big, but I think if I double it up I'll be okay.

All told I did about a 90% water change today. pH has been steady at 8.25 all day. One way or another, I think it's clear that every other day 50% water changes are just not frequent enough. I'll just have to do them daily.

 

[parshmar]

I use to know a guy that raised clowns in his basement. In each tank he had a piece of acrylic tube with an air stone in it, in addition to his airstones used for circulation. The length of the tube was basically right at the height of the water level or slightly below it. I never asked, but I bet he was just trying to control the o2 with them. I guess you could also use larger pvc pipe as well.

 

[Rascal]

That is actually a very effective technique. I use 3" - 4" pipe w/ 1" holes drilled throughout, then cover with Nitex. The pipe is an inch above the waters surface. An airstone is dropped inside and CO2 is degassed. This drives the pH up, and also allows O2 to diffuse into the water at the air/water interface.

 

[Rascal]

Oh, and be sure that that bottom of the pipe is capped so as NOT to act like a riser tube.

 

[NicoleC]

pH held steady through the night, dipping only to 8.23 from 8.25. I haven't figured out the aeration cage yet, but this morning I turned up the airstones in the front of the tank anyway -- the remaining larvae are mosly hanging out in the back corners.

Anyway, only 5 (I think) left today. I kept getting a count of 9 yesterday. So all this may be a red herring -- and issue, but not the real issue. I am not optimistic above the last few -- given the high mortalities at metamorphosis, even if they get that far they chances of any surviving are poor.

If O2 were a problem, wouldn't the larvae move to the surface and/or near the airstones? Or are they not smart enough for that?

 

[rsman]

a few issues, water movement tends to keep the level of o2 consistant so you wont have a real high point at least in a 1/2 full 10g. and then the fish have to realize the high points and be able to use them, these probibly are not that smart yet, and the surface water is harder to use.

 

[NicoleC]

Observation:

I have one goby that looks well developed and healthy. The others seem too thin and "hanging on."

Well, first I decided to cover the sides of the tank to reduce glare ala Wilkerson's Clownfishes. As I was watching, though, I saw the biggest one curl his tail (in a "S" curve, no less!) and jump after something. Hunting, I assume. The others are just jerking along as always. Anyway, I watched him do it several times. I have ot seen this behavior before.

I wish my silicon would hurry up and cure. You'd laugh at my aeration cages, but I think they will do the job. Hey, the tupperware kreisel works great.

 

[NicoleC]

Another observation:

Like the clowns, when I covered the back and sides of the tank, the gobies moved away from the back wall and started getting more active.

Oh hell. Could it really be something that easy?!
:hammer:
:spin2:

Just counted 8. So few -- but it will only take one adult to make me feel happy!