Upgrading 20L sump to larger volume?? Potential issues in chemistry/ balance??

[Barnabie Mejia]

Hello everyone,

we just closed on our dream home and I have a dedicated fish room now! I am going to be moving the 75g DT in there and I currently run a 20L DIY sump with a 8" water level in it and the tank is doing great. when I get the tank in the room I want to build a larger sump system to have better access to everything and I want to add more water volume.
The Plan:

I want to have the 75g bean animal drain into a 40B that will house the skimmer and have that overflow into a 100g tank (killer deal on offerup $40!! ) that will hold the marinepure spheres currently in the sump and other biomedia and act as a refugium. I would also like to add another tank about 50 gallons that would house live rock and will never have any lighting applied to it, this tank would have water pumped from the 100g and would overflow back to the 100g.
the tank for the rock would not be filled immediately with rock, that would be added in progressively to allow the tank bacteria to keep up with the surface area.

will I have any issues going from the 75g/20L volume to the 75g/40b/100g volume? I'm just scared that I will nuke the tank by causing a mini cycle or recycle. I have asked at my LFS and he danced around the question, but never gave advice.

Thanks guys and gals!

Barnabie

 

[shakacuz]

the way you have it planned out seems like it will work out how you want it to. just monitor ammonia/nitrate so you can avoid a mini cycle, but even so maybe having some bottled bacteria to counter it could help if it does come up?

 

[Barnabie Mejia]

the way you have it planned out seems like it will work out how you want it to. just monitor ammonia/nitrate so you can avoid a mini cycle, but even so maybe having some bottled bacteria to counter it could help if it does come up?

do you think the change in the water volume would be an issue? or am I over thinking that part of it?

 

[Randy Holmes-Farley]

Changing water volume generally leads to improved stability and little else of note.

For example, if corals use a certain amount of alk, the observed alk decline is lower, but the amount of supplement needed to boost it back is identical.

Aside from costing more to do a fixed % water change, or maybe more heating costs, there seems to be no drawbacks to a larger volume.

In my system, I had 2-3 times as much water in my sumps and refugia as in my main tank.

 

[Barnabie Mejia]

Changing water volume generally leads to improved stability and little else of note.

For example, if corals use a certain amount of alk, the observed alk decline is lower, but the amount of supplement needed to boost it back is identical.

Aside from costing more to do a fixed % water change, or maybe more heating costs, there seems to be no drawbacks to a larger volume.

In my system, I had 2-3 times as much water in my sumps and refugia as in my main tank.

Perfect, that makes sense and kind of what I was thinking in terms of stability. equipment for heating it has already been planned and the tank will remain on Auto water changes via hydros and my custom set up.

a side question @Randy Holmes-Farley I have about 1/2 - 1" of sand in the tank, I would really like to go bare bottom, what would be your recommendation of trying to achieve this? pulling out sand slowly over the course of 3-6 months to allow the tank to adjust? I feel like I have more than enough surface area between the rock in the DT and 2 gallons of marine pure spheres, and I will be adding a bio brick that has been seeding in a friends sump for a couple months.

 

[Randy Holmes-Farley]

Perfect, that makes sense and kind of what I was thinking in terms of stability. equipment for heating it has already been planned and the tank will remain on Auto water changes via hydros and my custom set up.

a side question @Randy Holmes-Farley I have about 1/2 - 1" of sand in the tank, I would really like to go bare bottom, what would be your recommendation of trying to achieve this? pulling out sand slowly over the course of 3-6 months to allow the tank to adjust? I feel like I have more than enough surface area between the rock in the DT and 2 gallons of marine pure spheres, and I will be adding a bio brick that has been seeding in a friends sump for a couple months.

It can probably be pulled at once, but do you have a picture of the tank?