91g Reef

91g Reef
91g Reef

After many years of absence I decided to start back up again with a modest 91 gallon aquarium. Here in Calgary finding a good LFS is hard as there are only a few scattered across the city. Fortunately when I walked into Wai's Aquariums I found a place I felt had good customer service and good selection of both dry goods and livestock. But boy was I shocked at the cost of everything. A yellow tang is $600, A small frag of Acropora is $50.


I picked a Red Sea Reefer 350 G2+ which is a 91 gal (342ℓ) total system volume tank. The main display holds 273ℓ of water and the sump 69ℓ. Funnily enough the system is advertised as 90 gallon yet on the warranty serial number sticker it is listed as 91 gallon. Since I already had two 90 gallon tanks I chose to pick the 91 gallon value for uniqueness.

The tank measures 120cm x 50cm x 53cm (L x W x H). Or for the confused Canadians - 48" x 20" x 21", or a 4ft tank. With the stand the system is 140cm high (55"). The front and bottom glass panels are ultra clear (low iron?) glass 12mm thick, and the two side panels are 15mm thick.

This model came with the ReefATO+ auto top-up system - but more on that later. When the tank was delivered, the cabinet had to be assembled - it was flat packed like Ikea furniture. The cabinet material is MDF, not plywood like some reviews mention. There are multiple adjustable feet to level the tank. I decided to place it on a rubber sheet that I got from Home Depot as this tank stands on top of a wooden floor in my living room on the first floor of the house. Without the rubber mat the feet would have had left dimples. That said, only once I tear down this tank will I know if that is not the case 😟...

The sump is nice and large, however I do have a couple of gripes with it. It fits almost too perfectly in the cabinet. It is almost impossible to remove the door from the hinge. It is nearly impossible to hook up any magnets or clip on clamps to the sides of the glass panels. There is only 1cm of clearance between the glass and the cabinet. I could not connect the Red Sea ReefATO clip for the RO water tube to the side wall as the clip needed 5mm more space. I would not have minded if the sump was smaller by 1cm both sides.

Mechanical Filtration

Previously I would have used the natural settling of the sediment in the sump as mechanical filtration, but I discovered a new and better way - a reef mat. I acquired a Red Sea ReefMat 500. The basic idea behind it is quite ingenious - the system lets the water from the overflow flow through a chamber where it is forced to go through a piece of filter paper that is on a roller, and once clogged up with sediment and other unwanted material, the sensor detects the rising water level and advances the roll to expose new filter paper. This lowers the water level and the process repeats. This way there is almost no maintenance - unlike sock filters that have to be cleaned regularly. Since this is new technology we will see how well it works.

I have a Red Sea Reefer DC Skimmer 600 - actually I purchased the AC version but it had a terrible humming noise echoing into my basement, and it over skimmed terribly for 3 days. So I got the DC upgrade kit and converted it - and could not be happier. The motor is a bit louder but the frequency of the noise is such that it is only audible in the room the tank resides in, I cannot hear it at all in my basement so that is a win. Also, with the DC pump I could dial it back and it does not over skim any longer.

Chemical Filtration

Underneath the ReefMat is a small holder for GAC 0 Granular Activated Carbon. I placed the small bag of GAC that was provided with the unit in the holder so that is currently my only chemical filtration. In the future I will consider adding a small Phosban 150 reactor with RowaPhos.

Biological Filtration

For biological filtration I have 40 lb. of dry rock (coloured pink and supposedly full of freeze dried bacteria - sounds a bit far fetched to me). Seems like live rock is something that one cannot really get any longer. I refer to the type full of life. I also bought 20 lb. of proper live rock from an old sump from an LFS - the rock is pretty barren but hopefully full of bacteria. I got another 7 lb. rock from Benjamin's Aquarium from their display tank - it came with some green star polyps and four mushrooms. I did not want those but what can you do? Perhaps they survive...

I moved one rock to the refugium.

The sand bed is shallow - about 40 lb. of aragonite and 40 lb. of aragonite Fiji pink sand, and 5 lb. of aragonite live sand. The first two bags was properly washed before I added it to the tank. The live sand sachet was empty so I guess no bacteria...


One 300W Eheim jager heater in the sump is responsible for maintaining a stable 25.0°C. It is currently set with an allowable range of 24.9°C - 25.2°C, reason being if I set it to 25.5°C the heater stays on during 00:00 - 08:00, when the house cools down to 18°C. Hopefully this saves some money and still be acceptable.

I have nothing for cooling - that is a worry for the summer.


The tank came with the Red Sea ReefATO+ that manages water level in the pump compartment, temperature and the pump in the RO reservoir - currently just a 5gal bucket.

I am not yet dosing anything.

Return Pump

The return pump is a Jebao DC Sine Wave DCP-5000 pump, capable of moving 1450 gph, with a maximum head height of 4m and consuming 40W. It is really quiet, and has a nice controller for speed control. No smart connectivity on this one.


Two Jebao smart wave makers, one MLW-20 and one MLW-30 supplies water circulation in tank, one on each side of the tank. They are programmable which is nice. I also just added a ReefWave 45 gyre pump to help with overall circulation. Between these three pumps I should be able to set up a flow pattern that covers all areas - hopefully.


Two Ecotech Marine Radion XR15 Blue and one XR30 Pro supplies the lighting for the tank. I still need to figure out a good schedule and colour balance that I am happy with.

In the refugium I have a Neptune GRO 20W LED which connects to the Neptune power bar - neat, one fewer power adapter.


The Neptune Apex Pro looks after the power bar, temperature, pH, ORP, tank water leak as well as RO tank water level. The Red Sea equipment have their own software and automations, and so too do the lights and wave pumps.

Water Parameters

All tests are done using Salifert test kits. pH, ORP and temperature are measured via the Apex. Salinity is measured using the Hanna HI98194 and pH and temperature are verified using this meter. I also have some Hanna colorimeters and when using that, I indicate it via (H).

Date Temp (°C) Salinity (PSU) pH Alk (dKH) Ca (ppm) Mg (ppm) NH3+NH4 (ppm) NO2- (ppm) NO3- (ppm) PO4 (ppm) ORP
29 Feb '24 25.4 32 8.0 6.9 385 1140 0.1 0 0 0.03 254
2 Mar '24 24.9 35 7.86 0.2 0 0.2 370
4 Mar '24 24.9 35 7.98 6.7 420 1370 0.15 0 1 0.1 361
5 Mar '24 0.01 (H)
6 Mar '24 24.9 7.98 -> 8.20 5.9 (S,H) -> 7.1 (S) 435 1335


I have no fish or coral yet so no feeding schedule as of yet.


No maintenance yet.

Power Backup

I have no backup power.