Tank Reset Help

[RandomD]

Before I start - long time lurker, first time poster. I can't find advice on my specific issue, despite a ton of searches, but if this has been covered in detail please just point me to a thread.
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OK, so I won't go into huge detail, but I've wanted a reef tank since I can remember, and about 16 months ago purchased a 105G (400L) system. I went 'big' on gear (skimmer rated to 2.5x my capacity, along with most things) and for a while, things went great. Lighting are the good quality aquaray's, 3 panels.

I was patient through the cycle, purchased premium live rock, had an auto-doser, auto-topup etc etc. My system isn't super high spec, my sump is just sponges, bio-balls, skimmer and pump, but everything is decent quality.

I had the tank moderately stocked, about a dozen fish and soft corals only, and about 3 months after stocking, the corals started dying off. At the same time, work and life got busy, and the tank was neglected. Then I went away for Christmas and things got worse, I put an auto-feeder in that was probably doing 2-3x the required amount.

At this point, the tank looked bad, I just didn't want to deal with it. I had 5 fish left:
Foxface
Blue Tang
Yellow Tang
Flame Angle
Clown

After a couple of months of just being depressed at the state of the tank, I got my LFS team to come over and 'reset' the tank. 70% water change, high pressure clean of the rock, redo of the electronics ect. The Ca, Mg, Kh levels were all OK, but the nitrates and phosphates were completely unmeasurable, for obvious reasons.

So, it's been 3 weeks since then, and everything looks a load better, my nitrates are now readable, but still about 64. I've been doing 3x 20% water changes per week, started vodka dosing and have been doing all the husbandry stuff I can think of or find. My levels of everything except Nitrate and Phosphate are spot on (I haven't checked anything my kits don't do), but those nitrates won't budge. My skimmer is producing around 100ml per day, and climbing. Within 24 hours of vacumming the sand, the algae is visible again.

So, I suspect that the live rock is leaching nitrate into the system, and the water changes are now just maintaining and slightly lowering the level, what else can I do? Is it just a keep doing the husbandry and wait?

I can't let this go to hell again, and I have the time to do it properly, looking for tips on what will help.

Thanks in advance to anyone who has ideas, apologies if I missed any important info.

 

[kmbyrnes]

First off, congrats for sticking it out. Things like this can make you want to quit.
I know it's tough, but remember, your tank didn't get that way in 3 weeks, and won't recover that quickly either.
Posting your actual parameters will help the group offer solutions.
Google 'Rapid Nitrate Reduction' for some reading links.
If algae is making a comeback, try going lights out for 3 days.
I'm sure others will chime in as well.

 

[RandomD]

First off, congrats for sticking it out. Things like this can make you want to quit.
I know it's tough, but remember, your tank didn't get that way in 3 weeks, and won't recover that quickly either.
Posting your actual parameters will help the group offer solutions.
Google 'Rapid Nitrate Reduction' for some reading links.
If algae is making a comeback, try going lights out for 3 days.
I'm sure others will chime in as well.

appreciate the reply KM, the parameters I can measure (from earlier today) are:
Alk 9.1
Ca: 425
Mg: 1300
PSU: 34.5
NO3: 64 (not sure if I trust this reading)

I can try lights out, but if the NO3 is whats causing the algae, wouldn't the correct thing be to target that? Apart from water changes, and my 2.5 weeks of vodka dosing, what else can I do in that space? I've gone the google route, and I don't really want to use chems to drop it, as all my reading points to 'attack the source'.

So, I've dropped my feeding massively, I really light pinch of of pellets in the AM, and half a frozen cube in the PM, the fish demolish it quickly.

If my rocks are making the NO3, is it just a waiting game? I can do that, but want to make sure I'm not missing a step somewhere.

Thanks for taking the time to reply, appreciate it.

And yeah, quitting did cross my mind - and is a real danger if this reset fails, so I'm determined to not give up.

 

[Chibils]

First of all, congrats on getting back up and giving it another shot. It can be really difficult.

I would consider replacing the bioballs in your sump with a rapid growing macroalgae like Chaetomorpha. It can chew through the NO3 and PO4 and when you remove a big clump from your sump you are very literally removing a big ball of nitrate and phosphate from your sump.

If you go this route, remove the bioballs slowly. After your rock got cleaned, it's probably maintaining most of your bio filtration. Removing them all at once is a bad idea. Chaeto will also need a pretty powerful light.

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[CarrieB]

Have you considered running GFO (granular ferrous oxide) to pull the phosphate and nitrate down?


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[Sk8r]

After a major problem, with nitrate higher than that, I'm getting results with NoPoX. Takes time. Lot of time. But persistence seems to be winning. Just don't push the system hard til you get that down.

 

[Reef Frog]

You've got some fish that can produce a good bit of waste. Most aquariasts, especially beginners, tend to really over feed. This coupled with the fact that you still have and immature and still evolving bio filter (bacteria) accelerates the nutrient issue.

Your options are to reduce the input (if you judge that wise) and/or implement or increase export tactics. GFO, Turf Algae Scrubber ATS, carbon dosing, detritus removal...and the list goes on.

It's really that simple but the devil is I the details and anything you do takes time to show results. But nutrient issues usually start with over feeding or too many big fish. Good luck and remeber it's almost always a passing phase.

 

[RandomD]

Hi all, thanks for the advice and support - appreciated greatly.

One more thing popped up today, I was doing a water change, and I vacuum the sand every time, the bits I can get to at least. The water comes out very, very clean - which isn't surprising seeing I'm doing it 2-3x per week.

There are a couple or rocks at the front that I can easily move, and this time I did - the sand at the bottom was filthy - really deep brown detritus, just horrible looking. I suspect all the sand that I can't reach is like this. I did some reading in another thread about substrate / vacuuming / do/don't and everyone has an opinion.

So, my question is: if the sand is genuinely horrible in the 80% of the bottom I can't get at with a vacuum, is that the likely cause of my nitrates refusing the budge? I've got a small CUC in there, few snails, hermits et al, but I doubt it's enough to repair the damage. While the tank is lightly stocked, should I bite the bullet and replace the sand, or at least pull it out and clean it properly?

If so, what knock-on effects could this have?

If I replace the sand, what would people recommend I replace it with? Live Sand/gravel/beach sand etc?

I would say it's about 1.5-2 inches deep at the moment.

Thanks again - owe you all one