question
 

My tank is doing some funny things and i would like some help.

it's a 20 gallon FOWLR and i currently have two small clarkii clowns and a scooter blenny and 6 hermit crabs and 1 snail.

my fish are not moving much and they seem to be breathing heavily. they don't go after the food during feeding time.

my parameters are:

salinity: 1.023
temp: 25 c
ammonia: 0
nitrite: 0
nitrate: 0
ph: 7.8-8.0 - i know it's a bit low but it was 8.3 just a few days ago.

i also had a sex line wrasse in it a few days ago and it died last night. all i did the last 2 days was a 20% water change and i added a new powerhead. i use water conditioner for my water changes. i'm not sure what else to test for my tank. any suggestions?

sounds like low o2. point a powerhead up to cause some surface turbulence.

do you run a skimmer?

+1 on the oxygen. Are you getting a film on the top of your water?

Ohhh i never thought of that. I pointed the powerhead more in an angle but how do i know It's getting enough oxygen? I also do not run a skimmer even though i have one. Thanks

Do you have any type of surface skimming, overflow or canister surface attachment?

if you can hook the skimmer up if not to skim at least for now to get some o2 in.

glass tops?

i do not have any surface skimming right now so i am really thinking it is low oxygen. should i use my old powerhead (it's really strong) to create more oxygen? i also have a power filter that is not in use. should i use that also?

no glass top. it's open. i will try to hook up my skimmer. i haven't opened it yet. was going to use it when i get corals.

mixing the surface is the key right now. you don't need more flow, just get the existing one rumbling the surface

what kind of power filter?
if is a aquaclear or similar plug it in and run it empty to stir it up