Tank just won't stabilize

[themericks]

Hi all,

I've got a tank that's been up for ~2-3 years, and it just won't stabilize. I'm stuck in a situation where my nitrate and phosphate are zero or nearly zero, but if I feed more I start getting tons of film algae growth on the glass and cyano growth on the sandbed/rocks. Same thing happens if I dose even small amounts of nitrate and phosphate. Same thing happens if I do less frequent water changes. Corals are surviving but looking a bit pale, for obvious reasons. I have some coralline algae growth, but it's not flourishing. Fish always seem happy and healthy. I've included as many details as I could think of below, hopefully someone can pinpoint what I'm doing wrong...I would greatly appreciate any tips or suggestions!

General tank features

• RSR 170 with sump
• ~30-40 lbs dry rock seeded with a few different bacteria in a bottle products (and some live reef rubble from AquaBiomics)
• Negative space, branching aquascape with very few dead spots
• 1.5-2 inches coarse white CaribSea aragonite dry sand, rinsed
• Sicce 1.5 AC return pump, full open
• Two Kessil A360s (intensity ramp from 0 to 50% over 3 hrs, hold at 50% for 4 hours, then ramp back down over 3 hrs), spectrum settings identical to intensity settings
• Two Aqua Gadget Midsize Pumps (253-2300 gph) set to 60% of max flow in sine wave mode, on upper back walls
• Comline 9004 protein skimmer, always on, cleaned and emptied once a week

Livestock

• 1 PJ Cardinal, 1 Royal Gramma, 1 Coral Beauty Angelfish, 1 Yellow Watchman Goby, 1 pistol shrimp, and 1 Clownfish (removed due to aggression ~1 month ago)
• ~20-25 corals, mainly frags with a few colonies, some on rocks, some on shelves
• ~10-20 snails (mix of trochus, astrea, and cerith), tons of micro collonista snails, and 1 tiger sand conch
• Tons of amphipods and copepods, numerous bristle worms and spaghetti worms

Parameters

• Alk ~9 dkH, Ca ~430 ppm, Mag ~1320, Phos ~0 ppm, Nitrate ~1 ppm, salinity ~35ppt, pH ~8.3
• I test all roughly once a week (Alk sometimes every few days) and all parameters are quite stable except phosphate which every now and then I'll notice spike up to ~0.1 ppm

Feeding

• ~1/2 cube of frozen Ocean Nutrition Formula 1 or 2 (alternating) every day
• Auto feeder with Ocean Nutrition Formula 1 and 2 flake mix, adding a small pinch a couple times a day

Water Changes

• Once a week religiously, siphoning the sand bed, scraping film algae off glass, removing cyano patched when needed
• During each water change, sand bed is always quite dirty. Siphoning pulls out lots of white detritus/silt, water in collection bucket is always a cloudy brown.

Dosing

• Started with Triton, switched to All For Reef a while back
• Daily dose of ~10ml All For Reef to keep alk ~9 dkH

Sump

• Ulva algae bed
• Kessil H160 grow light, on 6 hours at night (when display lights are off)
• A couple small chunks of live rock and rubble

 

[T-J]

Stop cleaning the sand bed and doing water changes. That will help your nutrients go up. I've never cleaned my sand bed. Ever. I also don't do water changes, but that's because I do the Reef Moonshiner's Method.

What's your PAR? What are you using to test your parameters? How are you dosing CA/ALK/MAG?

 

[themericks]

Thanks for the suggestions. When I stopped doing water changes in the past, the cyano/film algae growth takes off and seemed to adversely affect the corals. Just let that happen?

My PAR is ~150-200 on the upper rocks, ~50-100 at the sandbed depending on location. I test my Ca/Mag with Red Sea kits, Alk/Phosphate with Hanna kits (ULR for phosphate), and Nitrate with Salifert. I dose Ca/Alk/Mag with All For Reef, as I mentioned.

 

[Garf]

Are you getting loads of ulva growth in the sump?

 

[themericks]

Are you getting loads of ulva growth in the sump?

Nope, holding pretty steady. I used to harvest roughly 1 cup a week when I was dosing phosphate and nitrate, but not anymore since I stopped.

 

[Garf]

Nope, holding pretty steady. I used to harvest roughly 1 cup a week when I was dosing phosphate and nitrate, but not anymore since I stopped.

Depending upon what you’re using to increase phos, I’d be tempted to dilute it maybe into the ATO, see if the problems still occur with a low but consistent dose level. Don’t do anything yet though, sometimes I get odd ideas, lol.

 

[themericks]

I was using NeoPhos and NeoNitro before I stopped, so definitely doable. Thanks for the suggestion, I'll think about it.

 

[Nano sapiens]

The easiest way to help this situation is simply to look at a reduction in your export of nutrients.

Case in point. I had to leave my old small reef system for two weeks, so no bi-weekly water change/gravel vacuuming. When I came back, the aquarium's glass was a bit crudy, but the animals looked fantastic and had put on visible growth. So I made simple changes like reducing my water changes from 10% to 7% and gravel vacuuming less deeply/frequently. A month later and I can see the positive difference (always have had undetectable PO4, now more stays available in the system).

As in nearly everything reef related, slow and gradual changes are best. After a change is made, assess the results in a few weeks time to see if you are on the right track.

 

[Reefer_punk]

Try to reduce your feeding a little, 2 blocks of frozen is a lot. Better to clean the glass every day, than hit 0 of no3 and po4. Try to control that with adding that, but only when less feeding isn't the answer.

 

[themericks]

@Reefer_punk, I'm only feeding 0.5 blocks of frozen per day, plus a few small pinches of flake from an autofeeder spread out during the day. Do you still consider that too much?

@Nano sapiens, thanks, that makes sense, and is the general reef-keeping rule I try to follow. Just to be clear, every time I've eased off on nutrient control/water changes/etc (even slowly), there's been a marked increase in cyano/film algae/tank dirtiness to the detriment of coral health. Are you saying to just let that run it's course?

 

[Reefer_punk]

@Reefer_punk, I'm only feeding 0.5 blocks of frozen per day, plus a few small pinches of flake from an autofeeder spread out during the day. Do you still consider that too much?

@Nano sapiens, thanks, that makes sense, and is the general reef-keeping rule I try to follow. Just to be clear, every time I've eased off on nutrient control/water changes/etc (even slowly), there's been a marked increase in cyano/film algae/tank dirtiness to the detriment of coral health. Are you saying to just let that run it's course?

We feed that for about 20 fish and inverts in a 132 gallon. So yeah for me it is a bit much combined with flakes, which often contains a higher po4. Film on your glass (white is lack of po4, green is too much no3 in my experience) is something that goes witch it when you are balancing on the low.

 

[themericks]

Thanks, that really puts it in perspective, I think the first thing I'll try is to reduce feeding slowly. Never tried that, since it always seemed my issue was low nutrients without an apparent overgrowth of pest algae (though maybe it's the green film algae taking up all the extra...)

 

[JCM]

We feed that for about 20 fish and inverts in a 132 gallon. So yeah for me it is a bit much combined with flakes, which often contains a higher po4. Film on your glass (white is lack of po4, green is too much no3 in my experience) is something that goes witch it when you are balancing on the low.

You feed half a cube of frozen once a day for 20 fish? Are they all tiny? That doesn't seem nearly enough.

 

[Garf]

Thanks, that really puts it in perspective, I think the first thing I'll try is to reduce feeding slowly. Never tried that, since it always seemed my issue was low nutrients without an apparent overgrowth of pest algae (though maybe it's the green film algae taking up all the extra...)

You got a pic of the tank. I can’t help but think that you’re being guided down the road signposted “Dino’s this way”.

 

[Nano sapiens]

@Nano sapiens, thanks, that makes sense, and is the general reef-keeping rule I try to follow. Just to be clear, every time I've eased off on nutrient control/water changes/etc (even slowly), there's been a marked increase in cyano/film algae/tank dirtiness to the detriment of coral health. Are you saying to just let that run it's course?

I got the same crud/hair/bubble algae mess when I experimented by increased feeding to try and get detectable PO4. Typically, I don't test for PO4 as it's always '0' and just assess coral health (14 year old mature nano).

Each reef tank is unique and it would be presumptive for me to say that I know what you system needs. However, assuming lighting is not too bright, pale coral are often a sign of phosphate deficiency. I'd suggest staying with your feeding regime (assuming the fish are fed well and there's no excess food rotting away) as it is and just cut down a little on water changes and/or gravel vacuuming. If you see signs of hair algae/cyano, then you know you've gone too far and then can readjust to find a balance.

A good part of maintaining a successful reef aquarium constant assessment and management of input/output. It's a delicate balancing act for sure, but it is certainly achievable.

 

[Reefer_punk]

You feed half a cube of frozen once a day for 20 fish? Are they all tiny? That doesn't seem nearly enough.

Yeah about so, most of them graze the reef for pods or algae, or other critters all day.

 

[themericks]

Here are some pics of the tank as is today (I only scraped off a bit of film algae on the front glass a little earlier). Today is typically the day of the week that I would clean the glass, turkey baste the rocks, siphon the sand, and do a 5gal water change. Actually, that's partly why I posted today, I was staring at it earlier thinking "what am I missing?"

I can post other pictures if you want more detail on a specific area.

 

[Nano sapiens]

You got a pic of the tank. I can’t help but think that you’re being guided down the road signposted “Dino’s this way”.

That is often reported for young, immature tanks, but this one is 2-3 years old so *may* not apply due to rapid nutrient assimilation by the organisms). I've had my system show undetectable PO4 and less than 1 ppm NO3 for nearly a decade and had no issues (large bio load to water volume ratio with very rapid nutrient assimilation.

(EDIT: OP posted pics, so now the situation is clearer).

Hard to say in this case without a picture of the tank to assess the bioload.

 

[Reefer_punk]

Here are some pics of the tank as is today (I only scraped off a bit of film algae on the front glass a little earlier). Today is typically the day of the week that I would clean the glass, turkey baste the rocks, siphon the sand, and do a 5gal water change. Actually, that's partly why I posted today, I was staring at it earlier thinking "what am I missing?"

I can post other pictures if you want more detail on a specific area.

That looks like a bit of green cyano. Make sure your nutrients are detectable and dose some bacteria

 

[themericks]

In case it matters, the tank went through a pretty severe case of dinos early on (maybe ~6 months - 1 year old). But they faded over time, not sure I can attribute it to something I did.