Is it stupid to carbon dose a 30g? or better skimmer?

[CaptainDave]

Hey there, looking for a little direction.

I have a 30g cube that is about 6 months old. Overall, it's doing fairly well but I'd like to be doing better. My coral (mixed reef, softie/LPS/some SPS) are growing but not super fast, and SPS color could be better. I had a decent number of fish (ocellaris pair, Randall's goby, royal gramma, purple firefish, melanarus wrasse) and like to feed.

Phosphates are around 0.4, and nitrates (according to Red Sea test kit) are around 30. Obviously these need to be better. I have some, but not a huge amount, of nuisance algae, and a decent amount of hydroids. I have a Vertex Omega 130 that I've had trouble dialing in, perhaps because it's a little too big for the tank.

I've been reading about carbon dosing as a way to decrease nitrates and phosphates, and I'm wondering if it might be a good option for me as a way to reduce nutrient levels and continue feeding at appropriate levels.

So, the question is: are there any inherent problems in carbon dosing a tank this small (I would use Vodka, and start according to the table in the Reefkeeping article), or would I have a better result with downsizing my skimmer to a more appropriate size (maybe like a Reef Octopus 110INT or something?) that could more consistently skim the tank? My initial thought was that an oversized skimmer could overcome higher nutrients, but I'm having trouble dialing it in and now thinking that it's just too big.

Thanks for the advice!

 

[Portland]

Hi Cap:
I'm studying to set up a reef aquarium and from what I've read your numbers are fine for a 6 month old tank.

Reading the forums the the best practice/general consensus appears to be to change water on a tank your size using Ro/Di water. A simple 5gallon weekly is like 20% of your total column.

My understanding given water quality (which you've specified) is to look into lighting and water flow. In some cases I've read that sometimes all things being equal some times it just takes time for the tank and coral to mature where they hit their "stride" and will accelerate.

I haven't even begun my journey so I hope I'm not giving you bad advice, I hope some knowledgeable will chime in - im watching this thread with interest as I'm probably a year behind you good luck!

Edit - I just noticed you've been around since 2004 so maybe I miss spoke - if so my apologies

 

[flananuts]

I have a reefer 170 with octo 110int(about 43 gallon system). I think your nitrates would benefit coming down. Good news is you don't need much vodka for dosing. I used a spreadsheet I found on dosing to ramp up. It worked great. The skimmate output was more effective. Over time though by the addition of more corals I moved off vodka dosing and ran cheato in my sump. Now the tank bacteria is effectively keeping up without the cheato and vodka. I just occasionally now test phosphate using a Hanna checker when I test for ALK to keep an eye on things.


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[CaptainDave]

Thanks for the input. Additional info that may be helpful: I'm using IO Reef Crystals salt mixed with 0 TDS water from an RODI. I'm doing faithful 15% water changes weekly. I agree that this is a relatively young tank, but I think I should be able to get my nitrates down lower than they are now. Calcium is ~440 by Red Sea, Alk is 7.5-8 by Red Sea, Mag has been normal to high by Red Sea. Supplementation via Kalk reactor and BRS kalk, and BRS 2-part as needed. I'm running a fuge w/ chaeto and a couple filter socks, have some rubble and a block of Biopure in the fuge.

I'm going to order a Salifert kit to double-check my Red Sea kit because I'm not sure I believe that they are this sky-high, but I do think they are higher than I would like and so are the phosphates. Tank was started with Pukani dry rock but I used lanthanum until phosphates were zero before adding to tank, and phosphates were very low when I first set it up, so I don't think it's the rock.

I guess my main question is, would I do better in buying a skimmer that is better suited to this size tank (something smaller, like a RO 110INT or 110SSS), or should I just suck it up and carbon-dose? Stayed away from that for a while as I was afraid of bacterial blooms, but it seems like a good option. I bought some Prodibio stuff (Reefkit, mosly for the Biodigest and Bioptim) and just started using it, but I've been reading about Biodigest plus carbon dosing and people seem to have good results. Just wondering if this is overkill for my little 30 gallon tank and was wanting some input.

Portland, I appreciate your input. Yes, I've been at it for a while but I was out of the hobby for quite some time and don't have any experience with carbon dosing.

 

[CaptainDave]

I guess I should also add that I have an auto feeder dumping a very tiny amount of a mix of Sustainable Aquatics Hatchery Diet and Hikari Seaweed Extreme twice daily, and supplement every other day with a small amount of frozen food (usually Rods Food Nano but sometimes PE mysis). I also supplement with occasional phyto (we're talking a couple of drops) and BRS Reef Chili, but not much.

I could cut down the Reef Chili and phyto, but I'm not really willing to cut down on the feeding as my fish are happier and less aggressive when I stick to my current schedule. I'm thinking I'd like to increase nutrient export rather than decrease nutrient addition.

 

[cougareyes]

It all comes down down to managing your bioload. A protein skimmer may be your next logical step, but I dose nopox on my tanks and love it. I have a tendency to keep my fish very well fed, and even with an oversized skimmer that's dialed in and regular water changes I couldn't keep up. There is no problems I can see dosing a smaller tank, just start out on the lower side and adjust up. When you get it dialed in it can make you so lazy.

 

[Raintree]

Skimmers are rated more-so in regard to the bioload that you keep in a certain size tank although the volume of water does matter to some extent as well. Since you have not been able to keep nutrients down, the only logical conclusion is that your skimmer is not able to keep up. So no, i would not recommend a smaller skimmer.

Are you able to produce a wet skimmate? or no skimmate at all?

I'd recommend wet skimming, for a few days and then ease in to the carbon dosing (and continue to wet skim).

I agree that your phosphate is certainly too high (at that level it's probably very difficult for your hard corals to build a healthy skeleton) and nitrate is high too. I also agree that you can't really chalk this up to just being a "new tank", as you should still be able to manage nutrients.

A refugium with chaeto could help as well, or an algae turf scrubber if you can manage one

 

[CaptainDave]

Skimmers are rated more-so in regard to the bioload that you keep in a certain size tank although the volume of water does matter to some extent as well. Since you have not been able to keep nutrients down, the only logical conclusion is that your skimmer is not able to keep up. So no, i would not recommend a smaller skimmer.

Are you able to produce a wet skimmate? or no skimmate at all?

I'd recommend wet skimming, for a few days and then ease in to the carbon dosing (and continue to wet skim).

I agree that your phosphate is certainly too high (at that level it's probably very difficult for your hard corals to build a healthy skeleton) and nitrate is high too. I also agree that you can't really chalk this up to just being a "new tank", as you should still be able to manage nutrients.

A refugium with chaeto could help as well, or an algae turf scrubber if you can manage one

Thanks for the reply. The skimmer skims relatively wet, just does so very sporadically. The Vertex skimmers in particular have a reputation for being very finicky on undersized tanks (there are people using this skimmer on heavily stocked 120g tanks and doing well), so I was wondering if perhaps a smaller skimmer skimming consistently would do me better.

I have some chaeto in a small fuge section of my sump, no room for an algae scrubber.

I started vodka:vinegar dosing about a week ago and no problems so far, will keep everyone updated. I'm also using prodibio biodigest for some good bacteria base.

 

[Raintree]

Thanks for the reply. The skimmer skims relatively wet, just does so very sporadically. The Vertex skimmers in particular have a reputation for being very finicky on undersized tanks (there are people using this skimmer on heavily stocked 120g tanks and doing well), so I was wondering if perhaps a smaller skimmer skimming consistently would do me better.

I have some chaeto in a small fuge section of my sump, no room for an algae scrubber.

I started vodka:vinegar dosing about a week ago and no problems so far, will keep everyone updated. I'm also using prodibio biodigest for some good bacteria base.

A smaller skimmer may work better then if the skimmer is only skimming sporadically. It's difficult to say for sure though. One thing you could try is feeding smaller amounts of food more frequently, so the influx of food is more spread out--then maybe the skimmer will skim more consistently.


Carbon dosing should certainly help. Phosphate and nitrate ions do not interact with an air-water interface, so they can't be skimmed out on their own unless they are tied up in polar compounds (bacteria works too). best of luck

 

[Potatohead]

I have a 40g system with both a skimmer and I dose nopox. From what I understand you don't really want to carbon dose without a skimmer, as the skimmer is what pulls the nutrient loaded bacteria out of the water. I switched from another product to nopox about ten days ago and the difference is crazy. I used to clean my glass every 2-3 days, I haven't done it since I switched. My nitrate has gone from 8-10 to 5, and my skimmer pulls some serious gunk. The stuff is awesome.

 

[Piper27]

Stick with the carbon dosing and your skimmer will start working better. If not get a better, not smaller, skimmer. May need to use gfo for a little while if phosphates are really .4 and not .04 because vodka won't bring that number down much.
I dose 50ml of vodka and 50ml of vinegar daily and my skimmers have never worked this good. It's about a 400 gallon system.