Numbers a bit out of control NEED HELP

[TheClemsonKid20]

So I started an 18 gallon nano reef tank about three months ago. In the tank, I have 25lbs live rock, ≈8lbs live sand. Livestock consists of two Darwin clownfish, a skunk cleaner shrimp, purple dottyback and a linear Blenny. Also have two big snails, two smaller snails, and some hermit crabs.

I do a 3 gallon water change once a week.

I picked up a soft Xenia about three weeks ago, and over those three weeks, it’s basically shriveled up and died. This obviously alarmed me, so I ran the numbers on a Red Sea multi test kit.

they’re not great.

pH - 8.2
Nitrites - 0.1-0.2
Nitrates - 20-30
Ammonia - 0.2

seeing as I got this tank for free, and didn’t pick it, I may not be doing the filtration properly. It has an overflow in the top left that goes into chamber 1 of 3. The water runs over a sponge filter, and then drops in the chamber. I have my heater mounted here. From there the water is forced down and comes back up the other side of the divider Into chamber two. That’s the widest chamber. I had an extra three stage plastic media holder that goes in a jbj28 that I have placed in there. It doesn’t fit fully, so I have it angled. I have sponge, carbon, and an empty top slot. From there the water runs down again, to come out into the third chamber; which has the pump in it that sends the water back into the tank.

full disclosure; I had a hang on the back filter previously in a 90 gallon I had years ago, and it worked great. This setup I have now, is clearly not working.

anyone who is good at this stuff, can you please hold my hand and walk me through how to get this under control. Please talk to me like a 5th grader, because right now that’s kind of how I feel.

All the fish seem to be fine. Everyone is still happy and eating and acting like they always have. But I know they have to be feeling it too.

thank you so much for any help you can provide. These forums are a blessing.

 

[landlubber]

nitrite and ammonia are straight up poison to a reef system. if your tank is not properly cycled these will not be handled by the nitrification process.
i would take a water sample to your local fish store to confirm your findings but from here it reads like your tank has somehow fallen back into a cycle

 

[Dbichler]

Nitrites have little to no effect and your ammonia reading is probably false. Your nitrates are just a slight bit high but not overly. I would personally step up your water changes to 5 gallons or just more frequent until down to 10-20 instead of higher.

 

[mdb_talon]

The nitrites are irrelevant. The ammonia if accurate seems higher than expected but i am guessing not accurate unless you have had a lot of die off very recently.

Nitrates are higher than i like, but nothing to panic about in a tank with fish...and doubtful they were cause of xenia demise.

Agree with dbichler on water changes. What is alk level and have you been dosing anything(ie like ph booster which may have driven alk way up). Do you have phosphate test?

 

[Azedenkae]

Agreed with @Dbichler and @mdb_talon. Which brings up my question - what sort of lighting do you have? If the fish are fine but the coral died, might be an issue with lighting (or rather, a lack thereof).