My new Clearseal custom reef tank – reviewed

I work in the marine trade and get to work with thousands of fish and corals, and hundreds of tanks, every day. You’d think that would be enough to satisfy my saltwater cravings but earlier this year I bit the bullet and decided to set up another small reef tank of my own at home. When I say small, I mean three-foot small, as that’s all the space I had at the time and figured the limiting size of the tank would also help to limit my spending on it. 

Now I’ve got it some more space has become available, so the insatiable addict in me is wondering if I should have gone for a four-footer instead, but as far as tank design goes, I’m really happy with the choices I made.


I wanted a bare-bones reef ready system that I could populate with equipment myself and these days, there is loads of choice. Off the shelf, I could have gone for Red Sea, D-D, TMC, EA (I used to work there,) Nyos, Aqua One, Clearseal and Waterbox to name just a few. I didn’t want to go for a tall tank as I’ve got arms like T-rex, and I know from experience that not being able to reach the bottom means I won’t want to clean it as often, and I wanted this one to be mint. 

I wanted a weir box, which they all have, and herbie style plumbing, but wasn’t tied to a central weir box as I knew I could have a left-hand one because it was going next to a bookcase. I change my preferred sump designs like I change my socks. If I could just mix all their best bits together…


Closest to the tank I wanted to run this time were the Waterbox Frag and the D-D Reef-Pro. The Waterbox tank had pretty much everything I wanted including a funky shallow design, which although not to everybody’s taste, I’m known for my shallow home tanks and this was to be my third. At the start of 2020 availability on the Frag in the UK was patchy, and initial probing through the trade didn’t really get me anywhere. No one really knew the price either, although advertised at £1199 at the time of writing, its more than I wanted to spend. 

The D-D tank had everything I wanted this time including being wider than the tank was tall, corner weir and well thought out multi chamber sump. You could spec it for a Clarisea too instead of filter socks, and I knew I would head that way eventually so may as well ditch the sock option from the start. Note some other tanks listed above are sockless too, so Clarisea ready without any modifications. 

The only thing stopping me from ordering the D-D tank this time was that I wanted a dry cupboard section for electrics, which the 1200 model does have, but the 900 model doesn’t, and that market-leading cupboard height is just a bit too tall for me at 102cm high, when I was happy with 80cm high this time, as that plus tank height equals my perfect leaning-in height, and I don’t have to hang off my armpits when cleaning. So I guess I got to about a 90% perfect match for this home project but wondered if I could up it by a few more perfect with my own custom design. 

I spoke to Burscough Aquatics, my go-to, local bricks and mortar marine retailer. They do a lot of off the shelf and custom tanks and for their custom jobs lately, they’ve been using Clearseal. Seasoned fishkeepers will know the brand well, and I’ve literally had a Clearseal tank somewhere, my whole life. That’s just over 40 years, and I’ve still got one now, with metal stucco hood and plastic condensation covers. I’ve owned dozens of Clearseal tanks, sold hundreds in my time in aquatic retail and worked on two, monster, 9’ Clearseal custom build tanks in the past 12 months, so I knew they were up to the job. I got drawing and sent them my design for quoting.

I opted for a 900x600x375mm high rimless tank. That’s two feet front to back for scaping potential but only 15” high, so a nice, edgy design that is different to most reef tanks, while being super practical for coral placement and maintenance. For marines I always go for black silicone, and to better hide black coloured wavemakers and to make coral colours stand out I went for black acrylic corner weir and black vinyl wrap. The icing on the cake was low-iron glass on the front and two sides. 

The good thing about custom tanks and cabinets is that you can get pretty much everything you wish for if it’s possible to do, so I specced three holes for a Herbie, specced the diameter of the three holes and which corner I wanted the weir on. I also specced that I wanted both a top and bottom scavenging weir, which despite the low height of the tank, can be a nice feature for helping to draw detritus off the bottom of the tank. And Clearseal delivered. 

I also specced the cabinet height to my own perfect dims and cabinet design, both external and internal, to look like a standard Clearseal Reefspace on the outside but have a custom dry cupboard on the inside for electricals, which no other 900mm off the shelf reef tank has. And again, I got what I wanted. But I’m so particular on sump design and because I hadn’t yet decided what method I was going to use I left the sump out, because I had an eaProSump I could use until I made my mind up and tried out a few designs. 

A star is born

To be taken seriously in the reefing community a reef tank needs a reef related name, or just the word reef, a superlative, and a number, so I decided to call my own custom tank the SuperReef 3000, but in the real world, the bit of paper that came with tank says that it’s a Clearseal ReefSpace. If I were to market this tank its shallow design is definitely lagoon in style, so maybe its a Clearseal ReefSpace Lagoon, or a Clearseal ReefLagoon, or a Space Lagoon…who knows…I quite like Clearseal Super Reef 3000 Space Lagoon…and if you want a tank just like mine, I’m not precious. Its only five panes of glass at the end of the day, and you can have one. 

Build quality

In terms of build quality and silicone work I’d say it’s on a par with the D-D Reef Pro. Not the most immaculate silicone and glasswork I’ve ever seen but solid, built to last, and 100% built in the UK. I’ve never had the displeasure of having a Clearseal tank that leaks either, so that aided my choice to use them and satisfaction. They upped my spec of 10mm glass to 12mm too, and now I’m really happy that they did that, because the thicker the glass, the more quality a tank feels in my opinion. 

The weir box is massive at over 300mm long and 120mm front to back but I’m warming to it, and at least it means it will take some serious water flow. I didn’t spec the actual weir box dimensions although I did the holes, so if I ordered another one I’d probably spec a slightly smaller weir for what is only a 200 litre, three-foot tank, and would have specced a weir lid for it too. 

Custom means there are dozens of cabinet finishes to choose from so I chose one I hadn’t owned before – Pasadena Pine, but with push open, soft close, handle-less doors, from the outside the cabinet looks just like all the other brands and models listed above, which is a good thing because that’s how I like them. But if handles, pillars, gold leaf and a minibar are your thing, spec away.


With it being a corner weir I figured I could get away with just a single return blowing left to right across the tank, but I am a flow junkie so I’ll see how I get on with it and if I want more flow, I’ll file away a cut-out in the front of the weir too and Tee-off my return. I future-proofed it in one respect in that I can run 32mm drains and a 25mm return, which I intend to hard plumb all the way from the pump, so I reckon I could pump 6000lph through the system if I wanted to, or 30 times system turnover which is more than anyone should need, and the Triton guys only run 10 times system turnover which is still a lot. 2000lph for 10 times volume turnover through an EA single nozzle is easily achievable. So we’ll see.

In a perfect world, I’d have gone aluminium frame and adjustable feet, but that costs money when you go custom and I didn’t blag this one, I paid! But I’m high 90s % happy with my custom tank and when I’ve decided on a sump design, I’ll let you know. If you want to get yourself a tank like mine with all the above dimensions and specs, mine was £799 and didn’t come with sump or pipework, so once those are added on it puts right in the middle of the pack above in terms of pricing too, only without any of the features I didn’t want, all the features I did, and I didn’t compromise on anything.  

So I’m really, really happy with it, and can’t wait to get it set up. 

Clearseal is distributed exclusively across the UK to aquatic retailers by J&K. For more info visit the Clearseal website.


Jeremy Gay

Author of three fishkeeping books and lifelong fishkeeper. Experience includes editor of Practical Fishkeeping magazine, editor of Pet Product Marketing magazine, multi award- winning livestock manager and aquatic store manager.