Yup your two 110's should be fine, I would rinse pads out every time you change the water, in the dirty tank water. I would also stick with the one oscar in a 90 or 120. If you wanted another fish could add a pleco/catfish he could live with.
Weekends without feeding will be OK as well. Another random tip, I would make sure the top is quite secure in case he were to get pissed and try to jump when nobody is there because he didn't get fed.
You can also grow some pothos out of the top. Pothos are great at reducing nitrates.Welcome aboard
Yes 1 Oscar for the 90 gallon. You could do 2 Oscar's in the 120 and suggest bi-weekly water changes to keep Nitrate level low.
I have had experience with this, my prior Oscar loved to splash water on the lid or try to splash out the small holes in the back of the lidThis. Mine will knock glass lids open but just to toss water out.
Depends if one water change a week will keep the nitrates under 20ppm. The pothos plant can help lower nitrates and minimize the need for more water changes. Each weekly waterchange you could do a fin-level waterchange. Make sure you have some good filtration.I might be able to get a 72 x 24 x 18. The 18 is the height.
The seller thinks it’s 110 but I calculated closer to 135. Would this be a good size?
If I did two oscars, would I have to do multiple water changes/week as was discussed earlier in the thread?
Thanks again all