Two Tank System: How to mix the water of my 100G reef with 100G fresh salt water?

[friendlyguy]

Hi there!
This is double posting, but I did not receive any answers in my build thread: https://www.reef2reef.com/threads/red-sea-reefer-800-piggyback.779283/#post-8424684
So I am trying to get some help with the following question:
How do I best mix a running ~100g (390L) reef with ~100g (409L) of fresh salt water?

Background on this is: I joined a RSR 350 with a RSR XL 525... yes, I already did that.
(I connected both displays to the sump of the XL 525.)
The 350 is doing really well and its (probably) overstocked with corals.
ATM the 350 already runs on the sump of the 525.
The Display of the 525 is completely "unalive": there is only reef ceramik and coral sand in it.
As soon as I turn on the return pump of the 525 the two waters would start to mix, so currently there are only two Red Sea Reef Waver 45 running in the 525.
Of course I made sure to measure and harmonize all parameters I can, but apart from that:

Do you recommend mixing them as slow as possible or the opposite: something like "full steam ahead" (just turn on the return pump and start placing corals / fish in the new tank)

The Return pump does approx 2880L per hour with 1m of head pressure, I think I can run it as low as 1% (about 30L / h). In addition I could run the return pump at certain intervals to further slow down the mixing process.

Any recommendations on this one? Any experiences you are willing to share?

Thanks in advance!

 

[Phil D.]

IMO go slow on the two. You don't want to shock them and wind up with a bacteria bloom

 

[friendlyguy]

I am wondering whats considered slow enough? Something like days or something like 24hrs?
If I tune down the return pump to 1% 400L will be done in roughly 13 hrs. I could extend that period by using intervals. Like turned on for every 2nd hour for one hour: which would double the 13 hrs. Also: Its not just fresh water moving back to the sump: its a mixture of fresh and old water. So I think it would take at LEAST 13hrs times Interval to mix everything.

 

[CMMorgan]

Cool setup.... I'm +1 on what Phil said... go as slow as you can. Intervals are great. You may even want to consider a stopping point to recheck parameters along the way.

 

[friendlyguy]

@metzer: May i ask how you started your two tank system? Did you start both empty?

 

[MabuyaQ]

Go full flow from the start. There are no real producers in the second tank. The only 'producer' in the new tank could be the sand, as it may contain some organics. But nothing the corals or bacteria in a tank like the 'old' one you describe can't handle. Just let it run for a couple of weeks like that (swap some sand and if possible rock between old and new tank) for bacteria to colonize the new tank. During this time you can check up on dosing and other changes. Phosphates in rock and sand are always in an equilibrium with the phosphates available in the water, changing one (adding more sand and rock in your case) will change the other so you need to monitor this for some time. Then start moving corals over and/or adding more corals with some additional fish.

 

[friendlyguy]

Hi MabuyaQ!
Thanks a lot for your post. I am really struggeling to decide whether as slow as possible / full steam. So far we have 2 opinions on "slow as possible" and 1 "full steam".
May I ask you if you did this before?

 

[MabuyaQ]

Yes, I once set up a second tank even slightly larger than the existing tank on a single sump setup with a fully stocked and developed tank (7 years old). The only difference was I used liferock so had more organics to process than you will have to with ceramic rocks, but also a better bacterial biome already present from the start in the new tank.
The new rock contained quite some phosphate so had to run GFO for quite some time in a large amount where I previously didn't have to run any. Never had any ammonia, nitite or even nitrate spike though, put a tang and cuc in the new tank after 2 weeks and started stocking with corals.
I don't see a reason why it would be any different in your case. It will take longer to get a fully developed bacterial biome in the new tank because you are starting with ceramic rock, but as long as you keep it slow with adding fish this should not be a problem. Just put in a tang or other algae eater and diverse CUC as soon as possible and you can add all the corals you want.

 

[sharpimage]

If your alk is similar in both tanks, I would let it rip. If they were different but more than a point, I would let it run for a few hours, then off for a few hours. Repeat for a few days. Or when I forget or get bored which is most likely what will happen on session 2. If you have softies, I wouldn't worry about it too much. Sticks, a bit more worried

 

[skydirt]

I have a 400 main and a 105 frag tank on one sump. I got the 105 up and running while i finished the 400. the 105 ran for about 4 or 5 months with coral and fish before the 400 was complete. Once i filled the 400 and the parameters where the same i just lined them both up to normal operation. Was basically like a huge water change. I had no adverse reaction in the frag. I kept lights off on the 400 for 3 months with it just getting ambient lighting and added fish including 5 tangs to keep algae down. It has now been one year since frag started and I'm growing SPS in both.

 

[friendlyguy]

Thank you soo much for your responses!
I have plenty of live rock and corals that I plan to move to the new tank, as soon as they are mixed up, to help it to mature faster. 7 years is a much older system than mine, but reading the story from skydirt makes me a little bit more confindet.
That expansion was almost 4 times the amount of water than the "starting" system housed.
In my case its "only" 1:1

 

[Reefs and Geeks]

Think of it as a 50% water change. You're combining 50% old water with 50% new water. So as long as the parameters are close, you can safely let it rip and have both tanks ready to go in a matter of an hour or less. I've done this several times on my system, which is now 3 tanks plus a sump. Always worked well for me. For me, I'd just suggest temp, alkalinity, and salinity are on point between the two tanks before turning on the pump.

Nice build thread, by the way! Don't forget to get your build thread badge! it's nice so others can click on it as a hyperlink to see your tanks.

Off subject, but that light fixture you have in your room is awesome

 

[friendlyguy]

Thank you so much! All the reports from you, who did this in the past, make me feel more confident to do it.
Btw: I`ve just "claimed" that badge.
And... about that fixture: I like the "death star" design as well. Its nothing expensive though. Got it from ikea.

 

[metzer]

@metzer: May i ask how you started your two tank system? Did you start both empty?

I had an existing 750 up and running for about a year and then added the two 900s. At first, i kept both the 900s and 750 separate but the two 900s were tied together via a common sump. I had placed some rocks early on in the 750 sump, just a few pieces, to help establish some bacteria or seeding bacteria for the 900s. I started the two 900s empty, fishless cycle and blacked out for about two months with dry rock and a few pieces of the seeded rock. Fast forward about four months, i kept the two systems parameters close to one another, placed in some test corals in the 900s (none died) and ultimately tied them now together. Corals seem to grow (encrust) "better" in the 750 than the 900 but there a few differences in lighting and probably other factors as well.


Hopefully that helped answer your question.

 

[friendlyguy]

Thank you so much!

 

[friendlyguy]

To keep you guys "up-to-date": I`ve decided to adjust two more parameter: Nitrogen and phosphates.
I have Salinity, Alk, Temp, Ca, Mg in check.
Phosphate is off by 0.03 mg/l as in: current system 0.03 mg/l and the new one 0mg/l
Nitrate is off by 5mg/l.
I`ve ordered the hanna ulr checkers for nitrogen as well as phosphates, i hope they are accurate enough for this.