Where to begin? In my last update I mentioned the sand had started to look a bit green and generally manky looking (scientific term, lol). At the start of August I noticed a patch of sand at the back of the tank had developed a suspicious brown look to it. It didn't look quite like diatoms and warning bells were ringing so I dusted off the microscope for a closer look.
This is how the sand looked at the back...
...and this is what I saw under the microscope:
So yeah it was dinoflagellates but not a species I had encountered before, this was large cell Amphidinium. Apparently this species is not toxic to livestock but can be much harder to get rid of. The best way to tackle it is to outcompete it by encouraging the growth of diatoms, to do that you have to raise the silicate level so I ordered myself a bottle of Brightwell's SpongExcel. I have since found that this is not the cheapest approach as it's not very concentrated, Waterglass is much most cost effective but at least it would get me started. Apart from the dinos making the tank look dirty nothing seemed to be suffering or dying so I took my time with the dosing, starting off slowly. It's pretty hard to test silica levels with home kits, Hanna do make one but it's aimed at freshwater and doesn't work well for saltwater so I didn't see the point of buying it.
In addition to silica dosing I decided to get a better grip on the nutrient levels. At the beginning of August the nitrate level was around 2.5ppm thanks to dosing NeoNitro but phosphate was still extremely low often registering as 0 on the Hanna ULR. I invested in some NeoPhos and started dosing that too (bonkers really!).
A sand sample taken just over two weeks later looked like this...
There were still dinos present but now I was also seeing some diatoms mixed in as well. I continued to dose silica but still at a lower amount than is normally recommended. The phosphate level had risen to approximately 0.04ppm on the Hanna ULR by the end of August. By mid September I realised that the orignal brown patches at the back of the tank had faded away. I sampled the sand on the 11th September I couldn't find any Amphidinium under the microscope, this was honestly quite a surprise to me as I'd expected to see some still hanging around. So my sand was clean right? Well no, I had replaced one sort of brown for another.
This was the 'new' brown...
I stopped dosing silica and by that time the phosphate was up to 0.06ppm or thereabouts so I decided to hold off dosing any more of that too. By October the sand had progressed from brown to green when cyanobacteria decided to join the party too. It's even got the audacity to smile at me under the microscope!
At the time of typing this the sand is a mix of green and brown. I'm not so bothered about the diatoms because the CUC love it but the cyanobacteria is nasty. So how do I combat green Cyano? I did think about using Dr Tim's Re-fresh but it states on the bottle that it could be harmful to snails and shrimps. I queried this with the manufacturer but they wouldn't elaborate as to how serious the risk was or even how the livestock is affected, is it toxic to them or do they die because of a knock on effect? I'd also rather not use chemicals such as Chemiclean either. So I have an imbalance between the nitrate and phosphate levels right? They currently stand at around 4.5 ppm for nitrate (Salifert) and 0.06-0.09ppm phosphate (Hanna ULR, the test results vary from day to day). Should I keep raising the nitrate (I am still dosing NeoNitrate every day) or try and reduce phosphate, or do both? I did add a couple of new fish at the beginning of September in the hope of addressing the nitrate issue but there was no noticeable effect. Maybe I need to add a few more?
The struggle continues...
Not much new to report really, everything seems to be ticking along and there have been no new additions.
I harvested a load of macro algae from the refugium as the upper half was a completely solid mass. I think I might have been a bit over zealous with my pruning as the algae growth seems to have stalled somewhat since then. A knock on effect being that the nutrient levels within the tank have risen slightly. On the 9th January phosphate tested at around 0.046ppm and nitrate 0.35ppm using the Elos low range kits. When I tested again on the 10th January the phosphate level had crept up to 0.08ppm and nitrate to 1ppm. Hopefully once the algae growth picks up again the levels will stabilise as I don't really want the phosphate level to get any higher. I must get into the habit of harvesting smaller amounts of algae on a more regular basis.
I've also been chasing the male pintail wrasse round in the hopes of capturing a decent photo of him displaying to the female but boy, he's really fast! I have multiple shots of just his tail or the rear half of his body, lol. I am very persistent though, thank goodness for digital cameras or I would have probably given up by now.
I finally relented and moved the Balanophyllia to the sump, it was on the fast track to coral heaven if I left it in the DT thanks to the Pintail's attentions. It's so much easier to feed down there now, especially during the day as the refugium is reverse lit so it's nice and dark. The good news is whilst the flesh on one side has receded quite badly due to the earlier infection it doesn't appear to be getting any worse and it's certainly happy to start eating again. It's a pale shadow of what it once was, the photo below shows how far the tentacles currently expand (and the receded skeleton). I hope it improves and opens up fully again.
The green tentacled corallimorph was looking a little more extended than I usually see it during the day so I whipped out the camera for a quick snap of that too (with flash). It looks like an anemone (and is commonly called a ball anemone) but actually is a part of the mushroom family. It hitchhiked into my tank on a small piece of zoanthid rock and doesn't appear to have spread much in 8 months time, mind you neither have the zoas either, lol. I think it actually looks rather attractive.
I'll sign off with another short video. It's not much different than the last one I posted tbh but hopefully still enjoyable to watch.
When the tank hit one year old I sent off for another ATI ICP-OES analysis. The results of which are below.
Sooo, if it's not one thing it's another, last test the calcium level was a little low and now this time it's potassium. I don't currently own a potassium supplement and am debating whether I really need to order one now or not, I've never had to dose potassium before so it's a new one on me. The tin level is continuing to drop so that's one issue sorted and I seem to have hit on the right level of iodine dosing too. Nitrate and phosphate are still on the low side, I keep expecting them to rise as the tank gets older but there's not been much change yet. Despite this the coral growth is slow but steady and the colours are looking nice (well to my eyes they are at least) so I will continue as is for the moment.
Hi, my name is Lisa and I live in Derby, UK. I am a self-confessed reefaholic!