Purigen and cycling?

[artarmon42]

I know (from searching ) that people here use Purigen. So hopefully someone can help me out!

 

I started my Nano Cube just over 2 weeks ago.

It's got ~15lbs of LS and ~20lbs of (uncured) LR.

I had expected a cycle time of 2-3 months.

The back compartments are filled with LR and a bag of Purigen.

 

Anyway, my test kits finally arrived and I thought I'd test the water. Much to my surprise ammonia, nitrites and nitrates were all 0! I will re-check with a friend's test kit, but I'm pretty sure those results are accurate.

 

So that got me thinking... 2 weeks with uncured rocks seems really short (based on reading other people's experiences). I suspect it's the Purigen (apparently it absorbs ammonia, nitrites and nitrates).

 

So here are 2 questions:

1) I know some people say using Purigen during cycle reduces the spikes. That implies that Purigen does not pull everything out, which means maybe my tank IS cycled (just not with the right amount of good bacteria). Does that sound plausible?

2) If I pull the Purigen out, let the good bacteria grow to the right proportions, and then put the Purigen back in, will that reduce the good bateria back to the Purigen-aided levels? In short, taking it out temporarily would stress my tank without any real long-term benefits. Does this mean I will be reliant of Purigen forever (crack-additiction anyone )?

 

Thanks!

[Whitten]

Good question, as I to wanted to ask the very same thing.

[Aiptasia]

Purigen works best when the water is forced to flow through it as opposed to just sitting in a bag in your sump, so it's quite possible the purigen isn't pulling out that much in the way of nitrogenous wastes anyway.

 

It's easy to tell if it's being effective, simply remove the baggie and see if it's turning from light tan to dark brown/black. If it's darkened up, it is removing a lot of DOC from your tank. If not, it's probably not doing much good.

 

Using purigen in a new tank (prior to curing the LR and establishing the nitrogen cycle) can "stall" an aquarium from cycling properly. Even so, it's not likely the purigen will remove every DOC before it reaches the nitrogen cycle. I use my purigen in combination with reef carbon to help eliminate what my skimmer can't get out of the water.

 

The live sand/live rock combo you have for your tank is excellent. It's not unheard of for a tank to cycle out in that short of time provided there's been very little die off in the LR itself. Good quality live rock is a beautiful thing. The usual cycle time is about 3-5 weeks, but can be shorter or longer depending on the LR and the die off involved.

 

For a third test, take a small sample of your water into your LFS and have them test it for you there. Also, do you have any animals in the tank (snails, crabs, etc.)? Your janitorial/clean up crew would be the first thing I would add to your tank. Add them (1 snail per gallon, 1 little hermit crab per 2 gallons) and let them graze the tank for a week. If everything still tests out at zero/zero/zero, go ahead and start adding some corals!

 

No, you're not "hooked" on purigen. Think of DOC (dissolved organic compounds) as different dishes on a buffet table. While the purigen will limit two or three kinds of food on the table, it won't remove it all.

 

Chances are, you can safely ween yourself off the purigen. I like to use it in combo with reef carbon because I grow a lot of DOC loving algaes, which tend to secrete substances of their own into the water which can retard the growth of some corals. It's also good at removing yellowing compounds the way reef carbon can.

 

Is it absolutely necessary? no. Will it deprive your bacterial colonies of a potential source of food, slightly, but there are other sources for food constantly being produced by a living reef ecosystem.

 

It's like an air filter in a room full of chain smokers. It will filter some of the smoke out of the air, but unless all of the smokers leave or stop smoking, it won't ever completely purify the air. It just keeps the room from being "as" smokey as it would otherwise be.

[Whitten]

Good answer.

[artarmon42]

Thanks for the detailed explanation Aiptasia.

 

I took the bag out, and it's definitely darker. I'd say dark yellow, not quite orange. So it has changed a little (didn't know it'd go all the way to black eventually, so that's good information!).

 

My clean up crew (3 nas, 6 ast and 3 hermits) have been in there about a week now. I was following the "drop the crew in while the tank is cycling" theory, which seems to hold up quite well BTW.

 

I've decided to stick with the Purigen.

I figure if people are using technology (MH, chillers, RO/DI/UV) to keep reefs, some "high-tech" resin is going to be just another technology to help make my reef better.

 

Interestingly this whole experience and the research I've done into Purigen has now got me looking at Chemi-Pure and Poly Filter... things that I had not considered for use previously. Wonder what other "new technology" stuff is out there to augment the quality of my reef inhabitants!

 

Not to worry, I am looking at technology to suplement, not replace fundamentals. Still intending to do weekly water changes and all the basics

[Aiptasia]

Very good. Water changes are rule #1 in any aquaria, and if you can learn to dicipline yourself to change water, you're well on your way to success.

 

My purigen goes from being a tan/yellow to turd brown/black when it's exhausted. Check it weekly, and if it isn't turning dark, see if you can position the bag so that there's a stronger stream of water flow pouring through it. I use Red Sea prizm skimmers, which have a great media basket section for carbon/purigen that forces the water to flow through whatever media you put in it. Purigen works best when the water has no choice but to flow through it, where as carbon can still absorb substances with indirect water contact. Re-charge the purigen by putting it in a small bowl and filling it with a 1:1 mix of freshwater and household bleach. The bleach burns up the organics in the purigen within 24 hours and it will go back to the light golden tan color. Then, pour out as much water as you can and fill it with fresh water again, and add some de-chlor. Let this dechlorinated water bath sit for eight hours, then it's safe to use again. I usually let mine dry out completely just to be safe the cholorine has dissipated.

 

Having your cleaning crews in place from the get go is a great idea. I'm glad you went ahead and added them, as they're a constant supply of DOC for the nitrogen cycle to use as the tank/rock/sand cycles out. Provided your tank still tests out at zero across the nitrates, go ahead and start gradually adding some corals to the tank.

 

There's differences of opinion as how to go about doing this. I'm assuming you've thought about the kinds of corals you'd like to keep, and you have the right kind of lighting for these corals (top. middle or deep corals). Depending on their size, I like to start with two corals at a time. I take new corals and place them in a bowl with their bag water, then slowly drip the tank water into the bowl to acclimate them, with airline tubing and a crimp clamp. When the bowl fills up, pour off the water to just above the corals and do it again. By the second bowl full of water, the corals should be acclimated to the new tank water. This whole process takes me about 45 minutes before the corals are ready to be placed in the tank.

 

If you are buying your corals from your LFS, you can see what kinds of light they use and the position of the corals in their display tanks. If the lighting at the LFS is stronger than what you have over your tank, you can probably put your corals where you want them without light shocking them. If the LFS's lights are about the same intencity or less, you should place the corals on the bottom of the tank, or shelter them by placing them partially in a cave or under an overhang or arch in your LR. Give them plenty of time to adjust, even if they look shrunken and poor, and leave them alone until they begin to perk up. I've seen zooanthus and mushrooms recoil in horror after being moved repeatedly, only to adjust and open up after being left alone (to adjust on their own) for ten days to two weeks. Be patient with your corals, they will adjust their zooxanthellae all on their own and provided you have good water quality, will perk up soon enough.

 

When they're fully opening and look good, you can gradually move them to the position you want them to be in. The reason I like to give my corals two weeks, is so that they can acclimate fully and open up on the one hand, and on the other, so the tank can adjust to the new biomass. Going slow and not overcrowding the tank is very crucial with reef tanks.