Habitat - Indoor :: Help my tank won't cycle!

[Mia'sMomma]

Hello all!

I'm new here, and I decided to join this forum because I'm at my wit's end with my baby's tank. My baby's name is Mia and she's over 15 years old. I've attached a pic!

So I've been doing this a while and I thought I had it all figured out. But now her tank is refusing to cycle and staying all cloudy and green forever! I've attached a pic of the tank. Here's the details:

Tank: 75 gal

Lighting: 1 uvb bulb and 1 daylight bulb on the basking area and an aquarium light across the length of the tank

Filter: Fluval FX6 canister filter set up as recommended in this post: viewtopic.php?f=9&t=30145#p288910
Media: I used the same media forever and then I noticed last year it was wearing down a lot so I bought some fresh ceramic media and supplemented it. After the new media was added the tank still cycled just fine.
Blue filter sponge: I replace this 2x a year
Carbon: I usually replace this once a year because regenerating it makes me nervous. I replaced it last on January 26.

Cleaning:
I usually do a deep clean of the tank 2x a year. I do it when I see the tank is visibly dirty and the filter is not running optimally. I drain out 3/4 of the water. I take the rocks and the filter tubes and scrub them with the hose. I open up the filter and wash out all the filter components in a tub of water I've treated with water conditioner to remove the chlorine. Then I put everything back together and put water back in the tank by filling up the tub with tap water, treating it with water conditioner and then adding it back to the tank. I do it this way so that the chlorine won't kill the good bacteria sill in the last 1/4 of water. After the tank is full again I add some good bacteria according to the dosing instructions on the bottle. I leave all the lights on the tank off for 48 hours so the bacteria can grow a lot.

So I did a deep clean on April 14 and added bacteria, but the tank just never cycled and stayed green and cloudy. Even though I kept adding the bacteria on the recommended dosing schedule on the bottle. Which is unusual because I usually only need to add it once right after cleaning and it cycles just fine. I kept waiting and waiting for it to cycle until June 8th when I decided something must have gone wrong and I did another deep clean again. But the same thing happened and now it's June 24 and I just don't know what to do.

Good bacteria: I always use Microbe-Lift Special Blend to cycle my tank and it's worked really well for me in the past! I don't know why it's failing me now.

Readings:
Ammonia: 0.5 ppm
Nitrite: 0 ppm
Nitrate: 160 ppm
ph: 6.5
Temp: 79.0

Does anyone have any advice? I feel terrible that Mia is swimming in such awful water.

[steve]

I would stop adding bacteria and do partial changes. Carbon is usually replaced once a month. I also think you have a baby boy

[Mia'sMomma]

I would stop adding bacteria and do partial changes. Carbon is usually replaced once a month. I also think you have a baby boy

Thank you Steve! I'll do some partial changes and see if that helps. How partial were you thinking? Should a 25% change be sufficient?

And yea I figured out a while back that Mia was a male but since my little fourth grade self decided she was a girl I've stuck with that in my mind

[steve]

Yes, 25% should be fine. In the future, you can help preserve bio media by taking it out and keeping it in tank water while you clean out the tank. You can gently rinse it if you need to. And those digital aquarium thermometers are usually not too accurate, make sure you have a backup thermometer of a different type.