Otocinclus stay at water line.

I have been trying to increase my Co2 (via pollen glass diffuser in a 45-P, superjet es-600 for filtration/flow) to combat hair algea (dosing "E.I.Daily" , with 3 ml's macro solution and 2 ml of CSM+B saturated solution daily.) I read that hair algae is related to low Co2 and ammonia (I have no ammonia..)


I am at about 2.5 bubbles per second (I know, useless measure) and my Otocinclus at pretty much glued to the water line and sit there. I have been running it this high for a few days and they are still alive... so... I see no frantic gasping. Previously I was at 2.3 bubbles per second and they were still very lethargic, but did actively feed and swim during the day.... still not very active compared to lights off when I raise the lily pipe. Then they go crazy and come to life.


I have my lily pipe set so that the top of the glass is at the surface to get maximum surface agitation. I raise the pipe for several hours at night, so that my drop checker is blue in the morning. At the end of the day it is green-yellow.....


They aren't dead yet, but they just sit there all day at the surface.. occasionally one will swim around to go to another place at the surface.


Plants start pearling around mid-day through the eight hour photoperiod. I start the co2 1 hour before lights on and it goes off at the same time as the lights.


I am not sure if I have too much CO2 or too little O2. Any suggestions?


PS: for what it's worth, at my previous bubble count of 2.3 I had introduced 10 amano shrimp.By day two they were white, day three they were all dead.3 hour drip acclimation. They also just sat there, all behind one large rock.... Could 2.3 be too high as well, or could it be my almost nonexistent KH and GH levels?


I feel like I am chasing a dragon.

 

I had thought I read that it was caused by unstable CO2 and ammonia. My mistake... This is a six month old tank, religious monthly filter cleanings, no mulm... Great flow. Aquasky 451 is perhaps too powerful, but I can not add a dimmer (as far as a know) nor can I raise it higher. Over the course of several months is has really given my bolbitis a beating...


Regardless, my main concern for this post is regarding he behavior of my fish.

 

I bumped it down to 2 bubbles per second, an inserted some metal window screen between the LED's and the acrylic protector in my aquasky (so that you can't see the screen.) The Otos are moving more a lot ore but still seem to prefer to be near the top.


I am pretty nervous about turning the co2 down...


On hand, I have magnesium sulfate and calcium chloride. I did a water change and added a quarter tsp of each to five gallons of replacement water. Do you think this is enough? I have always been leery of messing with the GH because I seem to be incapable of keeping FW shrimp alive even after three hour drip acclimation (no problems with SW shrimp, ever.) I had assumed it was because I was using GH boosters in the past, so I had stopped (of course, shrimp still die..)