as i mentioned, gunk in the filter and gunk in the gravel will lend to high nitrates. water changes without a gravel vacuuming in a high nitrate tank will not do a whole lot to help the nitrate issue because the gunk is still there, breaking down and causing more nitrates. a gunky filter will act the same, the gunk continuously breaking down and adding to those nitrates.
i would not suggest a deep gravel vacuuming and a filter cleaning in the same day though, because that does increase your chances of removing too much beneficial bacteria and possibly causing your tank to go into a mini cycle.
50% water change is not huge. i've done three in one day of 50% on a 55 gallon. sure wished i had a python that day! lol!
look at it this way - a 30% water change will only remove 30% of the nitrates. so if your test result says 80 ppm before the water change, you will only be removing 24 ppm nitrates. that's 30% of the total 80 ppm, leaving you with 56 ppm, which still looks like 80 ppm on the card due to the closeness of the shades of red on the card. pretty hard to determine if any nitrates have been removed in this instance, eh?
i would not suggest a deep gravel vacuuming and a filter cleaning in the same day though, because that does increase your chances of removing too much beneficial bacteria and possibly causing your tank to go into a mini cycle.
50% water change is not huge. i've done three in one day of 50% on a 55 gallon. sure wished i had a python that day! lol!
look at it this way - a 30% water change will only remove 30% of the nitrates. so if your test result says 80 ppm before the water change, you will only be removing 24 ppm nitrates. that's 30% of the total 80 ppm, leaving you with 56 ppm, which still looks like 80 ppm on the card due to the closeness of the shades of red on the card. pretty hard to determine if any nitrates have been removed in this instance, eh?
kinda embarrassing.
