Oxygen in tank

[nmp80]

Hi,
The last time i tried starting my tank and added chromis, they died almost instantly, and i thought it must be an oxygen issue
i bought a tetra oxygen test kit,...has anyone used? I got a reading of 2, which is low on the chart... I have (2) eheim sprayer bars agetating the surface as well as a power head on the side of the tank, making a nice boiling effect on the top of the water..... oxygen level is still reading low... i have a glass top with two sections...i am keeping the flaps open for now, but i thought i should be able to close those to create an airtight seal...is that wrong? I also have 2 plastic peices on the back side of the top of the tank to create an airtight seal for evaporation
does anyone have any suggestions? Do i need more powerheads to circulate the bottom of the tank and the top of the water? Do most people keep the glass closed and sealed on the top? I am leaving about 1.5 inches of air between the top of the agetated water and the glass top...
any thoughts would be appreciated
thanks

 

[coralcor]

i think a protein skimmer adds air to the water not positive

 

[mahk]

Remove the glass top, they prevent o2 exchange as well as block light.

Evaporation is a good thing, not a bad thing. This helps with heat control

Coralcor is correct, protein skimmers add o2.

 

[bpfan64]

The reason your fish probably died was cause of shock, did you drip acclimate them???

 

[jojo1n2]

chromis's are usaully easy to keep. But lately Ive had nothing but bad luck with them

 

[afboundguy]

i think a protein skimmer adds air to the water not positive

Remove the glass top, they prevent o2 exchange as well as block light.

Evaporation is a good thing, not a bad thing. This helps with heat control

These two things would help with O2 exhange... And also putting in more powerheads would help with O2 exchange especially if they are aimed at the surface..

 

[nmp80]

thanks all for the replies...i have had terrible luck with chromis' lately...
i will keep the glass tops flipped open for now, but my understanding was i should be keeping them closed...
so if i have two power heads, would you recommend creating a circular motion with them? in other words...place one at the top shooting sideways and the other on the bottom shooting sideways to create a circular motion? OR do i put them both 3/4 of the way up the glass shooting up to the top since thats where most of the 02 exchange takes place?
thanks

 

[JayM]

If you have a skimmer the right size for your tank, you are getting more than enough gas exchange just with that. The open top and powerheads with surface agitation is just a bonus.....

 

[Doherty]

Where there lacs gas exchange there is a potential for a build up of Co2 in your water..... When Co2 combines with H2O(water in your tank) it forms carbonic acid which will drive down your PH down, as you know SW needs to be around 8.3, skimmer would be perfect for that needed for gas exchange. Do you have any ph issues in your system?