A Combo would be Best IMO...
A Combo would be Best IMO...
If you'll indulge me, I've been using most of the methods for a little while now, most recently the LaCl3.
Although the carbon dosing method works for some to control PO4, I think it's most effective at dropping NO3. If you feed anywhere close to generously, your PO4 will remain high well after your NO3 has bottomed out at 0ppm. Here's a brief summary:
500 Gallon [Rehabilitation] System:
- Roughly 8 years old; 6 of which was under-filtered;
- After 6 years embarked on Biopellets & GFO;
- Gradually worked my way up to an optimal quantity of BP (appprox. 2.5L) which eventually brought NO3 down from 100ppm + to 0ppm in about 8 months;
- While using BP I also embarked on an aggressive GFO regimen which was going through about 2.5lbs of GFO every 2 - 3 months. At best I was able to drop PO4 from about 2.0ppm to about 0.35ppm. As soon as the GFO would be exhausted, PO4 would inevitably climb back up toward 0.75 ish (leaching out of rocks; feeding; etc);
- After spending hundreds of $$ on GFO, I finally managed to rig up a LaCl3 system using a 5 gallon pail as a settling area, with all of the effluent going through a skimmer;
- After about 2 weeks (and a couple of heavy-handed doses while dialing this thing in), PO4 dropped from 0.75 to 0.02, but has fluctuated between 0.03 - 0.12 over the following month or two while I continued to dial in the drip and throughput; and while GHA and PO4; and cyanobacteria worked their way out of the system...
- Currently, the system is sucking a 1% dilution of LaCl3:RO/DI through the 5 gal pail and skimmer at a drip rate of apporx 1 drop per 10-15 seconds (24/7) alongside an aquarium water throughput of approx. 20 or so GPH - this seems to be keeping PO4 at 0.03 - 0.07 while GHA & cyano bacteria continue to work their way out, and I'm sure the LR is still leaching quite a bit of its 8 year storage
- This is my second cyanobacterial bloom on this system. I believe it was triggered by elevated PO4; a lapse in zeobak supplementation; while allowing the system pH to drop down to 7.75/7.90 (as a result of carbon dosing). There is no biotower on the system; the skimmer is well undersized; and there is no refugium... therefore I have to allow the DT drain to splash into the sump, in order to boost pH above 8.1. I've done this following my last water-change, and the pH is now holding at 8.2/8.3... I haven't resumed the zeobak routine fully yet, but am waiting to see if the cyano will run its course by simply raising the pH and blowing it off the rocks every now and again...
- In all I believe I am going through 1L of BP every 4 months (CAD$90 per 1L SWC Xtreme); and have only used 1/2 of my first (CAD $70 per L) bottle of SeaKlear despite my heavy-handed initiation
- As for GFO - I was spending about CAD $100 per two months to no permanent avail.
550 Gallon Public Reef (1000g TSV):
- 3 year Old System; 8% waterchange 2x per week; huge bio-tower; two refugiums; two large beckett recirc skimmers; very heavily fed;
- Aways used GFO at a rate of about 2.5 lbs every 4-5 months;
- Embarked on EtOH dosing about a year into the reef's existence at which point NO3 was hovering between 20 - 30ppm;
- Evenutally ramped up EtOH to drop NO3 down to 0ppm over the course of about 6-7 months;
- Despite EtOH & GFO, PO4 still only reached as low as 0.20 ppm;
- Took a break from EtOH due to the development of Cyanobacteria;
- After a couple of months, Cyano was resolved by focusing on raising pH back up from 7.8 - 7.9 to 8.05 - 8.15; by raising my carbonate hardness back up from 6.0/6.5 to 7.5/8. I also resumed EtOH dosing and began to supplement with zeobak;
- Took a little while but NO3 eventually got back down to 0ppm - at least until the next break from EtOH dosing (can't remember exactly what the reason was for this break); there was also another brief cyano outbreak
- Again the focus was to raise pH which had again slipped below 8... no more cyano in display tank, but NO3 is still holding at 10-18ppm and I'm still raising the EtOH dosage to drop back down to 0.
- In any event, the point here is that despite spending about CAD$100 per 3-4 months on GFO, the PO4 on this system still never dropped below 0.20 due to the heavy feeding...
- Just ordered a dosing pump so that I can setup a LaCl3 dosing system similar to that setup by Mike Cao (August TOTM).
So in summary for two large systems:
GFO is a very expensive option for large systems: approx. $100 per 2 months will not maintain trace levels of PO4 on a well fed system.
Carbon Dosing is very effective for NO3 control but does not effectively deal with PO4 on a well fed system. On a large system you can expect to spend approx. $90 per 4 - 5 months, but will achieve trace levels of NO3, but not PO4.
LaCl3 is extremely effective at achieving trace levels of PO4. on a large system you can expect to spend approx. $70 per 12 - 18 months even though it is heavily fed.
This of course is based only on my opinions generated from first hand observations. Keep in mind that I've only recently embarked on the lanthanum chloride method... but from all indication; I intend to stick with it as a compliment to any form of carbon dosing.
Regards,
Sheldon
