Cycling a new tank: should I do a water change yet?

[Redeyes31]

I am a few days shy of a month running my new tank. I originally filled it with about 20% RODI home mix with red sea coral pro salt and 80% LFS saltwater. Other than adding an ATO/Rez with pure RODI, the tank has just been running. No WC. I've been watching it and checking the parameters often. Trying to keep tabs on the Nitrogen cycle. Based on what I've read, I'm basically waiting for my tank to get dirty (diatoms, algae growth) as a sure sign that it's ready to start adding fish, inverts, corals etc. Also, I've read it's not good to do a water change until the cycle is finished, as it might lengthen the process. Only in the past couple days have I seen anything growing in my setup (possible diatoms in my refugium? picture below). Otherwise, my DT is crystal clean. I've also been watching my alkalinity drop over the month from 7.8 to 7.2, which is making me want to do a WC to get that number up, though I realize there is nothing in my tank (save for chaeto and an attempt at copepod seeding).

So my question: Think I should do a WC or wait until I see algae growth? My gut tells me to wait for algae growth.

For more info, my current parameters are:
PH: 8.3
Alk: 7.2 dHK
Salinity: 1.0255 (keeps moving btwn 1.024 and 1.026)
Amonnia: < 0.2 mg/L
Nitrite: <0.1 ppm
Nitrate: <5 ppm
Calc: 425 ppm
Mag: 1400 ppm
Phos: 0 - 0.01 ppm

About two weeks in my Nitrite was at 0.4 for a day or two and has been low ever since. About that time and for 4 days after my Nitrate was at 25. It has since dropped below 5.The parameters seem good!

Thnx

 

[Bill_Moorman]

What are you looking to accomplish with the water change?

From the results you posted your cycle is not yet over until you have zero ammonia and zero nitrites.

Hold tight Until you have zero of those parameters and then do a large water change to lower your nitrates before adding fish.


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[mcgyvr]

Have you been keeping the lights on in the display for 8 hours or so?
You can certainly wait another week or so and see how it goes..
If you started with dry rock its usually a minimum of 4 weeks so hold on still..

 

[Redeyes31]

Have you been keeping the lights on in the display for 8 hours or so?

Thanks for the comments!

Have not had my display lights on, though I have a sum light for the chaeto thats been running on a daily cycle.

Just getting excited to start adding some real life in there!

 

[mcgyvr]

Thanks for the comments!

Have not had my display lights on, though I have a sum light for the chaeto thats been running on a daily cycle.

Just getting excited to start adding some real life in there!

The fact that you haven't been running lights in the display tank is why you haven't noticed more algae growth..
Algae is photosynthetic and relies on light for fuel as well as nutrients..

IMO its best to run lights just to get the "ugly stages" over and done with quicker...
I'd suggest you run them for roughly 6 hours a day if you haven't been doing so already..

 

[nereefpat]

About two weeks in my Nitrite was at 0.4 for a day or two and has been low ever since. About that time and for 4 days after my Nitrate was at 25. It has since dropped below

FYI, the reason you saw this is because the presence of nitrite interferes with the measuring of nitrate. Any nitrite greater than zero will make your nitrate readings appear very high.

 

[Redeyes31]

I'd suggest you run them for roughly 6 hours a day if you haven't been doing so already..

I've got a couple detailed excel spread sheets I created and am trying to record everything. I forgot to comment as to when I started running my DT lights, and I wasn't sure the exact day. Then I realized, it was the day you posted this and it became plainly evident to me just how right you are!

So I pulled up 7/30 on my spread sheet and entered, "Began running DT LED"

I've got a C-ray 200 LED and set it to plant mode, lol. Came home today, 8/2, and my tank is DIRTY! Im stoked, thanks for the assist! :beer: