The Spec V is the cornerstone of the Fluval aquarium lineup, and is the inspiration of this website. It became my personal aquarium in 2013; I quickly fell in love with it and was motivated to share what I have learned about modifying and maintaining this great aquarium.
This review is now updated for the new and improved version of the Fluval Spec V, which phased out the older version around mid 2016. If you purchase a Spec V today, odds are you will get this new version.
As a quick overview, the Spec V is an all-in-one style of aquarium. This is to say that all necessary components (including light and filter system) are included. Furthermore, the filter and associated pump are enclosed within a special section of the aquarium – it’s truly all-in-one in this respect. The ‘V’ in the nomenclature refers to the tank volume – approximately 5 gallons. The tank is best suited as a freshwater aquarium, although some people have modified the basic version to operate as a saltwater reef. Finnex now makes available a special Marine version of the Spec V. The Spec V makes for a great planted aquarium, even with the stock light (more on that later).
I will run through what comes with the Spec V aquarium, describe how it works, give a few tips on setup, present some light performance data, and give some thoughts on the plusses and minuses of this aquarium. I will also discuss some of the differences between the new version of the Spec V and the old (Pre-2016) version. I’ve got another separate page on setting up your Spec aquarium.
What is in the Box:
The Spec V comes packaged very well. From a competent vendor (who ships within another enclosing box with packing material) it should be just fine in shipping. Here is a picture of the new box (updated version post-2016) which is mainly black:
Below (for reference) is the box for the old (pre-2016) version:
The thing that makes this aquarium so great is that it is an all-in-one configuration where the pump, filtration, and light are housed inside a single package. Inside the box you will find the followng: tank, filtration media (consisting of three parts – filtration sponge, carbon filter bag, biomax filter bag), pump, outlet tube, outlet nozzle, aquarium lid, LED light (with associated power brick), acrylic cover, and instructions. When unpacking, the acrylic cover is tucked in below the aquarium base.
Setup and Operation:
Here is the basic tank as it comes out of the box:
The basic tank construction is enclosed inside four walls of glass (and a glass bottom). Each corner of the aquarium is covered by aluminum quarter round pieces. I initially thought these were a bit clunky looking. However, after years of use I see the brilliance of these corner covers as they hide the algae growth that inevitably creeps in under the edges of silicone joints over time.
Even better, fluval now uses black silicone, which helps to hide gunk even better. The top edges corners are covered by a protective plastic piece.
The aquarium sits on a plastic frame. Spec aquariums used to be available in black and white, where the color was for the corner pieces, the bottom frame, and the light. Best I can tell, there is only one version now (with black trim).
The aquarium is internally divided into three sections that are separated by black plexiglass baffles. The sections are: main display section (where the fishies live), filter media section, and pump section. The filter media and pump sections have patterned glass to hide the insides from view – it is a very classy look and keeps the guts of the filtration system hidden.
As simple as the Fluval Spec V is, the filtration system is actually very good and mimics the operation of some high end aquariums by using an overflow and trickle-through media compartment. Flow starts at the pump that is located at the bottom of the pump section. Flow from the pump travels up an outlet tube and through the outlet nozzle that is mounted on the tank side of the divider. This outlet nozzle is a ball/socket type of mount that allows you some limited movement to direct the flow where you want.
I occasionally move this around to give the critters different flow patterns but usually leave it pointed up and slightly towards the adjacent side glass. Pointing it up helps create some ripples in the water surface to help maximize dissolved oxygen in the water. Water that is forced (by way of the pump) into the main display area then overflows into the filter section through the overflow slots.
Water then travels downward through the filter media and to a lower section (separated by a partial horizontal baffle that holds the filter sponge off the bottom of the tank). This lower portion of the filter section is open to the bottom of the pump section, which allows water to return to the pump inlet, and the cycle begins again.
If you wish to put a heater in your tank, you can either put it into the display area or better yet, some heater models are small enough to fit inside the pump section sharing space with the outlet tube. This is the option that I chose.
The instructions were not clear on exactly how to orient the pump at the bottom of the pump section; I found a position that worked best to fit everything in the space.
The pump is adjustable for flow rate by sliding a notch left to right. I initially thought that this would actually control the speed of the motor. In actuality, it simply slides a plastic plate to partially obscure the inlet slots of the pump to restrict or release flow. This picture shows the pump adjusted for maximum flow (+):
Here the pump is adjusted for minimum flow (-):
The filtration media that comes with the Spec has three parts: foam block, a bag of ceramic ‘biomax’ rings, and bag of charcoal. The foam block has two openings to house each of the bags of filtration media. Water flown downward through the various media. Fluval makes available replacement filter media specifically for the Spec line of aquariums. The filter sponge has a handy plastic handle that helps you remove/replace from the filter section, helpful for performing your regular maintenance.
The video below shows the aquarium right after I added the Seachem Flourite substrate. This particular substrate tends to cloud badly for a few hours after you put it in, which gave a nice opportunity to see the flow pattern through the tank:
The last two components to talk about are the Plexiglas lid and the light. The lid is a very good design. It is frosted along part of the surface which does a nice job of hiding water spots and hard water deposits over time. The cover does not enclose the entirety of the tank – the middle portion is open to the air. The edge of this center opening has a little lip internally and externally that seems to discourage critters from crawling (snails and red cherry shrimp) or jumping out.
There are four small pegs molded into the bottom that keep the lid centered and fixed to the display tank. There is a small rectangular opening over part of the filter / pump section that allows the cord to exit from the pump. I find this useful for dosing fertilizers or excel right into this section without having to mess with the lid at all and not having to dump things directly at the fish.
The light of the updated Spec V is greatly improved over the original version. It is much brighter and does not suffer from light droop. The light has a forked end that slips into a plastic bracket on the end of the tank.
The light construction is very unique: The housing is all aluminum and sits very level and sturdy on the aquarium. The housing is tub shaped; the LED lights are arranged inside this tub. What is very unique is that the void of this light is filled with some type of silicone. This was clearly an effort by the manufacturer to make the light as watertight as possible. This silicone material is slightly tacky. It will be interesting to see how it holds up over time, especially with respect to spots and hard water deposits.
The light is controlled by a touchpad on the top that toggled through off, on, and night mode. The light has 35 white LED’s and two blue LED’s. Night mode only uses the two blue LED’s; Daytime mode uses the 35 white as well as the 2 blue LED’s. The picture below has the old Spec V light (top) compared to the new:
The light has a separate power transformer brick and luckily, also has a cylindrical plug to attach/detach the light cord from the power brick. This is very handy when routing and arranging during tank set-up.
Since the Fluval Spec V’s strong suit is it’s small size and ability to fit in tight spaces (like a kitchen bar, where we have placed ours), I want to provide some details on the dimensions of the aquarium, both for overall size and for the size of various compartments. I have measured my Spec V as carefully as I can, down to the nearest 1/16th of an inch. Metric values are conversions from english and rounded to the nearest mm. Know that there will be some variance from unit to unit, but these numbers will be very close. I will keep consistent – width is along the narrow dimension of the aquarium, length is along the long dimension.
- Overall Footprint: Length = 20-1/2″ (521 mm); Width = 7-1/2″ (191 mm). The footprint measures the black plastic frame at the bottom; the actual glass dimensions are less than this.
- Overall Height: 11-3/4″ (298 mm). This is measured from the surface that the aquarium rest on to the top edge of the glass.
- Overall Height Including Light: 12-3/4″ (324 mm)
- Main Display Section: Length = 17-1/8″ (435 mm); Width = 6-3/8″ (162 mm)
- Pump Section: Length = 2-1/16″ (52 mm); Width = 2″ (51 mm)
- Filter Section: Length = 2-1/16″ (52 mm); Width = 4-5/8″ (117 mm)
- Filter Section Height: 9-1/8″ (232 mm). This is from the top of the baffle that the filter media rests on to the top edge of the glass
- Inside Height: 10-9/16″ (268 mm). This is for all compartments, measured from the top of bottom glass to the top edge of the glass.
The ‘V’ designation in the model name is supposed to represent the listed volume of the aquarium, which is 5 gallons. From the above values, I calculated the following volumes. Actual water volumes will be diminished with added decorations, filter media, etc. but it’s an interesting exercise:
- Overall volume: 5.59 Gallons (21.14 Liters). This includes water in the pump and filter sections.
- Display Section Volume: 4.99 Gallons (18.89 Liters)
Spec V Light Performance:
I tested the output of the Spec V light using a Seneye Reef Aquarium Monitor and PAR meter. You can read more on this page about my test methodology, but the basic premise is as follows:
- Use the Seneye light meter to test for PAR levels at 5 different locations through the tank: center and four corners.
- Tested at two different depths: 5″ below the water line and 9.5″ below the water line.
Here are the measured PAR values at 5″ below the water line (click on any graph or screenshot to enlarge):
66 PAR in the center. This is actually quite high and makes the stock light suitable for medium light plants and may even be able to raise some high light plants.
The light falloff to the corners is minimal and is fairly even.
Here are the measured PAR values at 9.5″ below the water line (around the level of substrate at the bottom of the tank):
This is very interesting. There is not much light falloff in the center when you go from 5″ depth down to 9.5″ depth. It is still 60 par down where carpeting plants reside. The light falls off more at the lower corners, but at an average of 43 PAR, it is still very good. It seems Fluval has really worked to arrange the LED’s so that the spread and penetration of light is perfect for this tank geometry.
I’d say this tank is perfectly suited for medium light plants. You may be able to raise some high light plants with good fertilizers and pressurized CO2 if you can be patient with slowed growth.
Here is a screenshot of the data from the Seneye Light meter reading. This is the center reading at 5″ depth:
Here is the center reading at 9.5″ depth:
For some reason, the Seneye meter did not report an accurate Kelvin reading of this fixture. However, if you study the graphs, it indicates a bit of a peak in the blue light frequency range. This matches what I see, which is a slight cool tint. Also note that the light falls off in the red spectrum. Plants grow well with light in the red wavelengths; unfortunately, this light does not produce much in the red range.
It’s a great light, but could be perfect if the light produced had more red and was a bit warmer overall.
One thing is for sure, the Version II (Post 2016) Spec V light clobbers the Pre-2016 light. Here is the PAR readings of the old light at the 9.5″ depth:
The old light delivers only 11 PAR at the bottom center of the tank. That is barely enough to serve a low light planted tank. I commend Fluval on the efforts they put into the upgraded light fixture.
As you can guess, based on me starting a website inspired from this aquarium, I’m very pleased with the Spec V. As great as the original version was, this new and updated version is even better.
The tank layout is very good. I love that everything is contained within one package. No separate canister filters or other equipment outside the tank that needs to be hidden. It is very sleek. The filter system works extremely well. Provided you practice a basic standard of maintenance and care, the filter system can handle a reasonable bio-load. I’ve used the same pump for 5 years and it has never skipped a beat.
I’m very impressed with the light. It’s construction is very high quality and I suspect that it will hold up very well over time. It is very sleek and vastly improved over the original. The touchpad toggle switch is very nice to use and much more robust than a hard slider switch.
I think that this model stands alone as the top all-in-one aquarium. Everything just works, from the filter to the light. The aspect ratio of the display tank gives you a decent space to arrange decorations or plants. The size of the tank is very reasonable and will allow you to place it in a number of locations. While heavy when filled with water, it is not so heavy that it needs an aquarium specific stand; it can be placed on a countertop in your kitchen or you can use a sturdy piece of furniture to hold it up. Despite being a nano aquarium, 5 gallons is enough to have some options for what fish and/or inverts you want to keep.
I love this aquarium and it has met my expectations. All of the downfalls that i can think of, when filtered through the very reasonable price for the whole kit, are really no big deal. With some ingenuity, most of the design deficiencies can be delt with through a few simple modifications or upgrades. Even with no mods, it is a perfectly great aquarium, especially if it is a fish only tank without the added dimension of live plants. Again, the all-in-one design is great. There are no filters hanging off the back or separate canister filters to hide. With some ingenuity, you can hide a heater in the pump section to hide it. The only thing that exits the aquarium are the pump cord and the light cord. I can see some compromises in construction to keep the cost down, but I’m glad that they designed it to be affordable. For the price, the quality and design is exceptional.
Thoughts for Modifying your Fluval Spec V:
I’ve got an entire section on tips for modifying your Spec V. Having said that, I’d be remiss to not mention a few possible tank modifications here as these are easier to accomplish during setup.
First, the stock Spec V comes with a bypass slot in the filtration system. You can see it a few inches from the bottom of the tank. It is an alternative path for water to enter the pump. It’s purpose is to keep the tank running if you ever let the water level get too low (below the bottom of the main overflow slots at the top). I feel that this bypass, while useful under some circumstances, is largely a detriment as it allows dirty water to bypass much of the filter. I prefer to close this bypass and force all the return water through the filter media. I have a page here that describes the pros / cons of this modification and gives instructions on how to get it done. It’s much easier to do this on tank setup before you have it full of water and critters.
Second, If you want to put a heater in the pump section of your tank, you need to punch some holes in your outlet tube. I go fully into the why and how on this page. You could perform this mod after the tank is setup; however, I’d suggest doing it right away if you have a heater in the pump section or if you want to lower the outlet flow of your tank a bit.
Wishlist for Improvements to Future Spec Aquariums:
The updated Spec V has tackled the biggest complaint I had with the original version, which was the light. The new light has a design that is much more appealing visually (thinner, doesn’t sag) and has higher light output. The addition of black silicone (instead of clear) was something that I had not thought of, but is a great aid in keeping the tank appearing clean.
I’ll cut to the chase. I only see one think that I’m disappointed with, and that is the light color. The intensity is good. The light color is way too blue. This may be a matter of taste – some people might light the blue-ish tint of this light. For most aquariums, especially those with plants, I think a more pleasing and natural look is with a warmer (color temperature) light. I don’t think it would need to be a major change – just a slight shift to a warmer color temperature LED.
If I could add to the wishlist, a dimmer would be nice. The light intensity is just what I hoped for; however, for lots of people the light may now be too bright. This could lead to problems for some tanks with increased algae growth. If a dimmer was added you could dial down the light a bit to match the needs and wishes of your setup.
I still wish that the pump/filter sections had just a bit more length to make it easier to install the pump and to fit a heater into the pump section. I got it all to fit, but just an extra 5mm or so would have made a difference.
Changes to the Updated Spec V (from the Pre-2016 Version):
For those who are familiar with, or own the old version of the Spec V (Pre-2016 version), here is a summary of all that I have observed that is changed between the two:
- The silicone is now black instead of translucent.
- The outlet tube (from the pump to the outlet nozzle) is now black silicone instead of translucent silicone.
- The pump and filter sections are now obscured by a pattern (small dots) instead of frosted glass.
- The light is entirely new. It has a much better construction (straight, sturdy, and bright).
- The light power brick is smaller. The cord arrangement is slightly different.
- The white version of the Spec aquariums is no more, all now come with black trim.
That’s about it. I consider all the differences to be positive, except for possibly the light color (it used to be a warmer yellow).