Advice Wanted - Setting up a new 120L

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lharrison94

Aquarium Advice Newbie
Joined
Sep 10, 2021
Messages
3
Location
Lincoln, UK
Hey everyone!

I'm quite new to the fish world, I've had a small tank with 3 Harlequin Rasboras since January and learnt that they absolutely deserve a much bigger tank with more friends so I've recently upgraded to a 120L and plan on adding more fish in future.

I'm currently doing a fish-in cycle in the new 120L tank with my 3 Harlequins and my levels have remained the same for the past week, the levels are:
pH: 7.4-7.6 (they are in the tricky mid-range on the API test kit)
Ammonia: 0.25ppm
Nitrite: 0.50ppm
Nitrate: 0ppm

My question is this - Do I need to be doing anything extra/anything different? My Ammonia and Nitrite levels are very low but not at 0 yet and I'm seeing absolutely no Nitrate. Do I need to add more fish yet to get a more effective cycle going or is it best to wait it out? I'm planning on adding 3 or 5 more Harlequins to complete their group but I'm not sure if I should do that in the next few days or wait more weeks until the Ammonia and Nitrite is at 0?
I am also wondering what is the best way to lower the pH as it is a tad high at the moment and I'd like it to be down to at least 7 for the fish I plan on adding in the future (Corydoras, Shrimp, Rummy Nose Tetra).

More Info:
My tank is planted and I have been using API Quick Start to add Beneficial Bacteria when doing water changes and of course the Aqua Safe to remove chlorine. I've been doing 50% water changes every day.
 
Your target should be to keep ammonia + nitrite combined below 0.5ppm. Are your readings before or after the 50% water change you mention? You arent too far off that target so good job there. If you are seeing those readings before your water change, maybe cut back to 25% change and see where you are the following day.

I would hold off adding any more fish until you are consistently seeing 0ppm ammonia and nitrite in your daily test without needing to resort to water changes to keep them there. This could take several weeks.

Do you have any access to filter media from a cycled tank? Perhaps you have a friend who keeps fish who could let you have some? Introducing a little established filter media into your filter is the best way to seed your filter and speed up the cycle process.

What is your pH? Unless its way out there dont try anything to chemically alter it, just let it sit where it naturally wants to be. Fish are very adaptable to pH levels and all you end up doing by trying to alter it is have the pH swinging about between where it wants to be and where you are trying to get it. This is stressful for fish and causes more harm than good. Some driftwood should lower it a little, in a safe manner. But its really not needed.

Edit: I see your pH now. Its fine at that pH.
 
Last edited:
Hi! My current routine is to do a water change at about 6pm-8pm and I test the water the next morning at about 8am-9am, so the test results I'm getting are 12 hours before I do the next water change. Is it better to test a few minutes before or after a water change instead?

I still have my old tank running with its filter (no fish) so I could try using that media :)

My pH is reading on the high end of the pH test (7.6) and on the low end of the high range pH test (7.4) so I'm not 100% sure what the actual pH is (I'm using the API Master Test Kit). If the pH isn't too much of an issue though then I will leave it and not worry about it like you suggested, don't want to mess about too much and stress the fish out!

Thanks very much for your help so far! :)
 
Be consistent with your water testing so you can compare in comparable situations. I would suggest doing it immediately before or after your water change and opinion will vary on which is best. When i do a test i do it before a water change so you can see your water at its worst, many people recommend doing it afterwards to ensure your water change had the desired effect. Some people test before and afterwards. When you are cycled and things are running smoothly and you are more comfortable, i guarantee you wont test much.
 
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