Comparison

HYDROS App vs ReefATLAS PAR Estimator

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

HYDROS App

Easily monitor and control your aquarium's vital parameters like temperature, pH, and salinity. Manage all your connected devices, including ATOs, lights, and pumps, with a user-friendly interface. Quick setup with preset configurations means no coding is required to get your system running.

Highlights
  • Monitor temperature, ORP, pH, salinity
  • Control ATO, lights, heaters, pumps
  • User-friendly interface
  • Quick setup with presets
  • Manage multiple devices and aquariums
  • Set schedules and create modes
Features
Read full description

Use the CoralVue HYDROS App to control and monitor HYDROS aquarium devices from your smartphone or tablet. The user-friendly interface allows you to easily monitor your aquarium's temperature, ORP, pH, alkalinity levels, salinity, and more. With just one tap, you can control your ATO, lights, heaters, pumps, skimmer, calcium reactor, RO/DI units, etc. Setup is quick and easy! With 18+ different preset configurations and growing, it will take only minutes to get all of your equipment set up and running, with no coding required. SUPPORTED DEVICES: -HYDROS Control X2, X4, XS, XD, X3, X4, XP8, X10 -HYDROS Kraken -HYDROS Minnow -HYDROS Launch -HYDROS WaveEngine, WaveEngine LT -IceCap Gyre Dual Pump WiFi Controller DISCOVER MORE: -Intuitive interface features multiple view options such as tile, text, or graph -Adjust your view settings to light mode, dark mode, or auto, which will automatically adjust to your mobile device's settings -Ability to manage multiple HYDROS devices and aquariums from one single-screen -Monitor and control WiFi outlets -Set schedules and create modes -Archive controller settings STAY CONNECTED We welcome you to join our HYDROS community at forum.coralvuehydros.com where you can ask questions, learn more about your HYDROS devices, and connect with other aquatic hobbyists like yourself.

About

ReefATLAS PAR Estimator

This app helps reef aquarium enthusiasts estimate and visualize light distribution without a PAR meter. It allows users to input tank dimensions, lighting equipment, and water conditions to predict PAR levels and make informed decisions about coral placement and lighting setups. The tool offers interactive 3D visualizations and supports a wide range of popular reef lighting systems.

Highlights
  • Interactive 3D PAR heatmap visualization
  • Support for popular reef aquarium lighting systems
  • Multi-fixture light array setup
  • Fixture placement and angle controls
  • Spectrum and intensity adjustment tools
  • Custom tank dimension configuration
  • Surface agitation and lid modeling
Features
Read full description

ReefATLAS PAR Estimator is a subscription-based aquarium lighting analysis app built for reef keepers who want a smarter way to estimate light levels without always having access to a PAR meter. Designed for reef aquarium hobbyists and professionals, ReefATLAS PAR Estimator helps predict and visualize PAR distribution using tank dimensions, lighting equipment, mounting height, spectrum settings, fixture intensity, water conditions, lid transmission, surface agitation, and other key variables. The goal is simple: help reef keepers make better lighting and coral placement decisions before guessing, moving coral blindly, or copying someone else’s lighting schedule from a different setup. FEATURES • Interactive 3D PAR heatmap visualization • Support for popular reef aquarium lighting systems • Multi-fixture light array setup • Fixture placement using a top-down tank layout • Support for mixed light models in the same setup • Individual fixture height, position, rotation, and angle controls • Master/slave light grouping for linked fixtures • Spectrum and intensity adjustment tools • Manufacturer-style spectrum presets where available • Custom tank dimension configuration • Manufactured tank catalog support • Glass thickness and internal dimension calculations • Surface agitation / shimmer adjustment • Lid type and lid cleanliness modeling • Salinity-aware estimate adjustment • Project save and load functionality • Local device-based project storage • Optimized for reef aquarium planning and coral placement SUPPORTED LIGHTS ReefATLAS PAR Estimator includes modeled profiles for many popular reef lights, including AquaIllumination, EcoTech Marine, Kessil, Red Sea, ReefBreeders, Maxspect, Fluval, Illumagic, REEFi, Orphek, Philips CoralCare, NavaReef, Noo-Psyche, GHL, Current USA, and more. View the current supported light list here: https://thereefatlas.com/par-estimator-lights New lights and tanks are added regularly. If your light or tank is not listed, the app includes request buttons so you can send it in for review. Requested lights are prioritized for modeling when enough manufacturer/spec/PAR reference data is available. HOW IT WORKS Configure your aquarium dimensions, select your lighting equipment, adjust fixture placement, mounting height, spectrum, intensity, water conditions, and lid settings, then generate a 3D PAR distribution estimate throughout the aquarium. For single-light setups, quickly model one fixture over your tank. For advanced systems, the Light Setup tool lets you place multiple fixtures across a top-down tank grid, including mixed models, different mounting heights, fixture rotation, and angled mounting. The estimator calculates each fixture’s contribution at each point in the aquarium and combines overlapping light output to create the final PAR estimate. This helps represent real-world multi-light setups where beams overlap, spread, and converge across the tank. IMPORTANT ACCURACY NOTE ReefATLAS PAR Estimator is an estimation tool. A real PAR meter will always be the most accurate option for measuring your specific tank. However, many reef keepers do not have access to a PAR meter. This app is designed to provide a better starting point than guessing by combining modeled light profiles, tank dimensions, fixture placement, spectrum settings, mounting height, water depth, lid transmission, salinity, and surface agitation into one interactive estimate. Accuracy depends on available fixture data, setup inputs, and real-world variables such as rockwork, coral shading, water clarity, lens condition, and surface movement. SUBSCRIPTION REQUIRED ReefATLAS PAR Estimator requires an active monthly subscription to access and use the app. A subscription purchase is required to use the PAR estimation tools and features shown in the App Store screenshots and description. Privacy Policy: https://thereefatlas.com/privacy Terms of Use: https://thereefatlas.com/terms

Screenshots

HYDROS App3 screens
ReefATLAS PAR Estimator4 screens

Verdict

The call

The clearest difference is rating: ReefATLAS PAR Estimator at 5.0 against HYDROS App's 3.6. ReefATLAS PAR Estimator also leads on update cadence (daily vs every 3 months). HYDROS App's advantage is in-app purchases (none vs 1) and ratings volume (23 vs 1). On price, ads, device support and iOS requirement there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. ReefATLAS PAR Estimator sells 1 in-app purchase, starting at $4.99 per month. HYDROS App asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

ReefATLAS PAR Estimator holds the better App Store score, 5.0 against 3.6. That said, the two scores are not equally well evidenced: HYDROS App has 23 ratings behind it against 1, so its average is the more settled of the two.

UpkeepUpdate frequency

HYDROS App ships an update every 3 months, ReefATLAS PAR Estimator daily. The most recent releases landed on October 22, 2026 and October 19, 2026 respectively.

Scorecard5 real differences · 5 level
HYDROS App versus ReefATLAS PAR Estimator: the parameters behind the verdict, then further details
ParameterHYDROS AppReefATLAS PAR Estimator
PriceFreeFree
Rating3.6 (23 ratings)5.0 (1 ratings) — better
Positive reviews62.3% of reviews—
Number of ratings23 — better1
Update frequencyEvery 3 monthsDaily — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterSubscription
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.614.0 — better
Further details — not scored
Size70 MB27 MB
Age rating4+4+
DeveloperCoralvueJONATHAN ALBERT PITTMAN

Customer experience

HYDROS App

All ratings22 ratings
Positive63.6%
Neutral9.1%
Negative27.3%
Written reviews77 reviews
Positive62.3%
Neutral7.8%
Negative29.9%

ReefATLAS PAR Estimator

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

HYDROS App

No in-app purchases

1 purchases

ReefATLAS PAR Estimator

Subscriptions1
  • ReefATLAS PAR Estimator Monthly$4.991 Month

Questions

Is HYDROS App free?
HYDROS App is free to download, with no in-app purchases.
Is ReefATLAS PAR Estimator free?
ReefATLAS PAR Estimator is free to download, with in-app purchases available.
Which has better reviews, HYDROS App or ReefATLAS PAR Estimator?
ReefATLAS PAR Estimator is rated higher. HYDROS App averages 3.6 out of 5 from 23 ratings, while ReefATLAS PAR Estimator averages 5.0 from 1 ratings.
Do HYDROS App or ReefATLAS PAR Estimator have ads?
Neither HYDROS App nor ReefATLAS PAR Estimator shows ads.
Which is updated more often, HYDROS App or ReefATLAS PAR Estimator?
HYDROS App ships an update every 3 months, and ReefATLAS PAR Estimator daily. Most recently, HYDROS App was updated on October 22, 2026 and ReefATLAS PAR Estimator on October 19, 2026.

Other comparisons