Issues with Biodiversity and Chaeto Growth in My 180-Gallon Reef Tank

[stokedmuffin]

Hi everyone,

I’m hoping to get some advice on an issue I’ve been dealing with in my 180-gallon mixed reef tank.

For the past year, I’ve been performing weekly water changes of 100-125 gallons to manage phosphate and nitrate levels. However, despite the water changes, I’m noticing that my tank isn’t building the biodiversity I would expect. Specifically, my chaeto (macroalgae) in the refugium has stopped growing and is even starting to die off more each week.

I’m wondering if the frequent large water changes are preventing the tank from establishing a more stable ecosystem, as it might be constantly resetting the biological life and nutrient cycling.

Has anyone experienced similar issues or have suggestions on how to approach this? Could reducing the water change frequency or adjusting other factors in the system help resolve this?

Thanks in advance for your help!

 

[Liquid361]

That’s a massive water change!!! I believe it’s recommended to do around 10% every couple weeks at most? What types of filtration are you using? Tank age? Reactors? Lighting? Share your system.

 

[GSPClown94]

What are your phosphate and nitrate measurements? Could there be some testing error? Water changes are probably not the best way to reduce phosphate, consider GFO or Lanthanum Chloride instead.

 

[BryanM]

salinity, alk, phos, nitrates? Maybe a couple of tank pics?

 

[stokedmuffin]

Hi everyone,

I’m hoping to get some advice on an issue I’ve been dealing with in my 180-gallon mixed reef tank.

For the past year, I’ve been performing weekly water changes of 100-125 gallons to manage phosphate and nitrate levels. However, despite the water changes, I’m noticing that my tank isn’t building the biodiversity I would expect. Specifically, my chaeto (macroalgae) in the refugium has stopped growing and is even starting to die off more each week.

I’m wondering if the frequent large water changes are preventing the tank from establishing a more stable ecosystem, as it might be constantly resetting the biological life and nutrient cycling.

Has anyone experienced similar issues or have suggestions on how to approach this? Could reducing the water change frequency or adjusting other factors in the system help resolve this?

Thanks in advance for your help!

What are your phosphate and nitrate measurements? Could there be some testing error? Water changes are probably not the best way to reduce phosphate, consider GFO or Lanthanum Chloride instead.

no3 50
po4.5
kh 8.3
ca 420
mag1335
i am using Salifert test kits the tank is professionally service every other week and i do it of the off weeks. i started the large water changes under his advice to deal with the no3 and po4 until the tank was established enough . i am currently running gfo and bacto balance for carbon dosing. and for food the tank gets half a ounce of rods herbivor blend frozen food twice a day .

 

[stokedmuffin]

It's a little messy right now

 

[BryanM]

Going to need a fuge expert to chime in, but with those nutrient levels I would think you'd be able to grow cheato without much issue.... I went a different route using an aglae turf scrubber.

The tank itself looks good to me so I am guessing biodiversity isnt all that bad, its just a cheato issue.... But I am indeed guessing.

 

[stokedmuffin]

I'm saying bio diversity because the tank isn't processing any waste.I have to keep the numbers down with large water changes . The cheato was growing pretty well for a couple months

 

[stokedmuffin]

I am also doseing a gallon of pods and over 2 gallons of phyto every week

 

[helmsreef]

What light are you using for your fuge and how long do you run your light for? What does your source water test at? Seems odd to me that your nutrients are hovering around that high with such large water changes.

 

[BryanM]

And a lot of other filtration in that sump. Very "strange".

 

[stokedmuffin]

What light are you using for your fuge and how long do you run your light for? What does your source water test at? Seems odd to me that your nutrients are hovering around that high with such large water changes.

i am using 1 neptune gro light on the top and 2 Tunze lights on the bottom i think they are running for 12 or 14 hours . one would think with water changes like that i would be bottoming the tank out but that isn't the case. just seem to be wasting a lot of salt

 

[BryanM]

Does that skimmer produce a lot of skimmate? Do you feed a lot?

 

[Subsea]

Seaweed growth is not controlled by the most abundant nutrient, but growth will be limited by the least abundant nutrient. Iron is a major trace mineral that often should be dosed.

In my experiences, Chaeto is not the most efficient nutrient export seaweed. However, dose some trace minerals. Many use ChaetoGrow, I prefer organic kelp concentrate.

 

[Subsea]

i am using 1 neptune gro light on the top and 2 Tunze lights on the bottom i think they are running for 12 or 14 hours . one would think with water changes like that i would be bottoming the tank out but that isn't the case. just seem to be wasting a lot of salt

If you are spending that much on salt, then spend the money to get ICP test so you know what is missing.

 

[stokedmuffin]

Seaweed growth is not controlled by the most abundant nutrient, but growth will be limited by the least abundant nutrient. Iron is a major trace mineral that often should be dosed.

In my experiences, Chaeto is not the most efficient nutrient export seaweed. However, dose some trace minerals. Many use ChaetoGrow, I prefer organic kelp concentrate.

I am doseing tropic marin a and k elemnts im also doing monthly icp test and dose any elements found to be low. It was only a little low on iron last time and I did dose that .

 

[stokedmuffin]

If you are spending that much on salt, then spend the money to get ICP test so you know what is missing.

I do monthly icp test

 

[stokedmuffin]

If you are spending that much on salt, then spend the money to get ICP test so you know what is missing.

 

[Subsea]

Manganese, iron & molybdenum are low. When was the sample made and what have you done about it?

 

[stokedmuffin]

Manganese, iron & molybdenum are low. When was the sample made and what have you done about it?

I think it was about 2 weeks ago. And as soon as I got the result, everything on the test was corrected.According to their recommendations.